[vfs, #3] All file reading code goes through the VFS now, new mod downloader & mod selector in place. Also a bunch of other stuff. (...)

- HTTP networking support, mods can be downloaded via the builtin downloader.
  All network activity runs in a seperate thread, which is started
  as soon as any network activity is requested.
- The master server is hard-coded to fg.wzff.de/aqmods/ if not specified otherwise;
  this setting can be overridden in the config file.
- The mod selector screen is now a grid-view for much better navigation;
  also works with joystick.
- VFS code is functionally similar to the old molebox-packed release
  for win32. The game could also have its data shipped in a Zip file
  or any other kind of archive.
- It is still possible to build without VFS support, but then the mod
  downloader and soft-patching will not be available.

The full commit history can be found here:
https://github.com/fgenesis/Aquaria_clean/compare/master...vfs

The most important commit messages follow:
[...]
    This replaces all std::ifstream with InStream, and fopen(), ... with vfopen(), ...
    Some code is #ifdef'd for better performance and less memory-copying.
    VFILE is defined to whatever type of file is in use:
    - FILE if BBGE_BUILD_VFS is not defined
    - tttvfs::VFSFile if it is.

    Other changes:
    - [un]packFile() is now unused and obsolete. That code has not been adjusted to use VFILE.
    - glpng can now load from a memory buffer.
    - TinyXML uses the VFS for reading operations now.
    - The rather clunky binary stream loading of glfont2 got replaced with ByteBuffer,
      which gets its data in one block (necessary to use the VFS without implementing
      a somewhat STL-compliant std::ifstream replacement.)
-------------
Implement loading mods from zip files.
-------------
Implement soft-patching game data files. (Replacing textures/audio/... on the fly)
-------------
Misc bits:
- Extended GUI focus handling a bit
- Fixed weirdness in texture loading... not sure but this seems more correct to me.
  Actually, considering that the texture will have its native size after restarting the game,
  the lines removed with this commit seem pretty useless.

Aquaria/ScriptInterface.cpp

@@ -713,6 +713,26 @@ static bool findFile_helper(const char *rawname, std::string &fname)
 	return exists(fname);
 }
 
+static int loadFile_helper(lua_State *L, const char *fn)
+{
+#ifdef BBGE_BUILD_VFS
+	VFILE *vf = vfs.GetFile(fn);
+	if (!vf)
+	{
+		lua_pushfstring(L, "cannot open %s", fn);
+		return LUA_ERRFILE;
+	}
+	else
+	{
+		int result = luaL_loadbuffer(L, (const char*)vf->getBuf(), vf->size(), fn);
+		vf->dropBuf(true);
+		return result;
+	}
+#else
+	return luaL_loadfile(L, fn);
+#endif
+}
+
 luaFunc(dofile_caseinsensitive)
 {
 	// This is Lua's dofile(), with some tweaks.  --ryan.
@@ -720,7 +740,7 @@ luaFunc(dofile_caseinsensitive)
 	findFile_helper(luaL_checkstring(L, 1), fname);
 
 	int n = lua_gettop(L);
-	if (luaL_loadfile(L, fname.c_str()) != 0)
+	if (loadFile_helper(L, fname.c_str()) != 0)
 		lua_error(L);
 	lua_call(L, 0, LUA_MULTRET);
 	return lua_gettop(L) - n;
@@ -732,7 +752,7 @@ luaFunc(loadfile_caseinsensitive)
 	std::string fname;
 	findFile_helper(luaL_checkstring(L, 1), fname);
 
-	if (luaL_loadfile(L, fname.c_str()) == 0)  /* OK? */
+	if (loadFile_helper(L, fname.c_str()) == 0)  /* OK? */
 		return 1;
 	else
 	{
@@ -763,7 +783,7 @@ MakeTypeCheckFunc(isText, SCO_TEXT)
 #undef MakeTypeCheckFunc
 
 // special, because it would return true on almost everything that is RenderObject based.
-// Instead, return true only for stuff created with createQuad() 
+// Instead, return true only for stuff created with createQuad()
 luaFunc(isQuad)
 {
 	RenderObject *r = robj(L);
@@ -2192,7 +2212,7 @@ luaFunc(getWorldType)
 {
 	luaReturnNum((int)dsq->continuity.getWorldType());
 }
-	
+
 luaFunc(getNearestNodeByType)
 {
 	int x = lua_tonumber(L, 1);
@@ -2703,7 +2723,7 @@ luaFunc(spawnIngredient)
 	if (times == 0) times = 1;
 	bool out = getBool(L, 5);
 	Entity *e = dsq->game->spawnIngredient(getString(L, 1), Vector(lua_tonumber(L, 2), lua_tonumber(L, 3)), times, out);
-	
+
 	luaReturnPtr(e);
 }
 
@@ -2728,8 +2748,8 @@ luaFunc(spawnParticleEffect)
 	if (!layer)
 		layer = LR_PARTICLES;
 	float follow = lua_tonumber(L, 7);
-	ParticleEffect *pe = dsq->spawnParticleEffect(getString(L, 1), Vector(lua_tonumber(L, 2), lua_tonumber(L, 3)), 
-		rot, t, layer, follow); 
+	ParticleEffect *pe = dsq->spawnParticleEffect(getString(L, 1), Vector(lua_tonumber(L, 2), lua_tonumber(L, 3)),
+		rot, t, layer, follow);
 	luaReturnPtr(pe);
 }
 
@@ -5896,7 +5916,7 @@ luaFunc(entity_isPositionInRange)
 	if (e)
 	{
 		if ((e->position - Vector(x,y)).isLength2DIn(lua_tonumber(L, 4)))
-		{ 
+		{
 			v = true;
 		}
 	}
@@ -7101,7 +7121,7 @@ luaFunc(setLiPower)
 {
 	float m = lua_tonumber(L, 1);
 	float t = lua_tonumber(L, 2);
-	dsq->continuity.setLiPower(m, t); 
+	dsq->continuity.setLiPower(m, t);
 	luaReturnNil();
 }
 
@@ -7118,10 +7138,10 @@ luaFunc(getPetPower)
 luaFunc(appendUserDataPath)
 {
 	std::string path = getString(L, 1);
-	
+
 	if (!dsq->getUserDataFolder().empty())
 		path = dsq->getUserDataFolder() + "/" + path;
-	
+
 	luaReturnStr(path.c_str());
 }
 
@@ -8928,7 +8948,7 @@ Script *ScriptInterface::openScript(const std::string &file, bool ignoremissing
 		lua_getglobal(baseState, "v");
 
 		// Load the file itself.  This leaves the Lua chunk on the stack.
-		int result = luaL_loadfile(baseState, realFile.c_str());
+		int result = loadFile_helper(baseState, realFile.c_str());
 		if (result != 0)
 		{
 			if(result != LUA_ERRFILE || (result == LUA_ERRFILE && !ignoremissing))
@@ -9250,7 +9270,7 @@ bool Script::call(const char *name, void *param1, void *param2, void *param3, fl
 int Script::callVariadic(const char *name, lua_State *fromL, int nparams, void *param)
 {
 	int oldtop = lua_gettop(L);
-	
+
 	lookupFunc(name);
 	luaPushPointer(L, param);