Drop Travis CI

The build has been red for years anyway, so it's not as if it was providing any
value.

.travis.yml

@@ -1,52 +0,0 @@
-# http://docs.travis-ci.com/user/build-configuration/
-language: cpp
-
-sudo: false
-
-compiler:
-  - gcc
-  - clang
-
-os:
-  - linux
-  - osx
-
-#matrix:
-
-#branches:
-#  only:
-#    - master
-
-addons:
-  apt:
-    packages:
-      - libopenal-dev
-      - libsdl-dev
-
-before_install:
-  - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then brew update          ; fi
-  - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then brew install sdl openal-soft; fi
-
-script:
-# ALL THE BUILD COMMANDS HERE
-  - export CMAKE_PREFIX_PATH="$CMAKE_PREFIX_PATH;/usr/lib/x86_64-linux-gnu/"
-  - CMAKE_OPTIONS='-DCMAKE_PREFIX_PATH='"$CMAKE_PREFIX_PATH"' -DCMAKE_BUILD_TYPE=RelWithDebInfo -DAQUARIA_INTERNAL_FREETYPE=OFF -DAQUARIA_INTERNAL_LUA=OFF -DAQUARIA_INTERNAL_OGGVORBIS=OFF -DAQUARIA_INTERNAL_OPENAL=OFF -DAQUARIA_INTERNAL_PNG=OFF -DAQUARIA_INTERNAL_SDL=OFF -DAQUARIA_INTERNAL_TINYXML2=OFF -DAQUARIA_INTERNAL_ZLIB=OFF'
-  - rm -rf cmake-build
-  - mkdir cmake-build
-  - cd cmake-build
-  - cmake $CMAKE_OPTIONS ..
-  - make -j 2
-
-notifications:
-  irc:
-    channels:
-      - "irc.esper.net#bitblot"
-    skip_join: true
-    use_notice: true
-    on_success: change
-    template:
-      #- "[%{commit}: %{author}] %{message}"
-      #- "%{build_url}"
-      - "[%{repository_slug}#%{branch} @%{commit}] (%{author}): %{message}"
-      - "Diff: %{compare_url}"
-      - "Build: %{build_url}"