Initial commit adding support for detection of SGX. Not tested yet.
Increment version number due to binary incompatibility of the
sizes of cpu_raw_data_t and cpu_id_t.
Previously, 0.2.1 was mentioned in libcpuid.h, but this was not,
actually, in effect; it wasn't mentioned in autoconf and Visual Studio
project files. Also, cpuid_lib_version() still returned "0.2.0".