CMake build scripts

[Frost-54]

Added CMake support and fixed some compile errors.
Compiles on latest version on Windows/Mac/Linux, but fail to compile on some older platforms(likely a compiler problem).

Summary:

1. #undef linux on linux, because linux is defined by the compiler and used as an identifier.
2. Added github CI.
3. Cast return value of MAKEINTATOM to LPCWSTR because some functions expect a LPCWSTR not LPTSTR
4. Make closeSocket a wrapper function on Windows because the compiler complains.
5. Call to CreateMasteringVoice in IXAudio2CreateMasteringVoice is not valid.
6. Most HRESULT error codes are larger than INT_MAX. Wrapped them in an 'enum ErrorCode'. Use ErrorCode in each ErrorCategory::message(). Also convert HRESULT to ErrorCode before passing to std::system_error.