New command 'make' and 'config' for oryol build script
Only run cmake if needed with new 'config' option
Minor fixes to make UnitTest++ compile and run with emscripten
New emscripten build configs for building with unittests
Minor tweaks to compile on emscripten/OpenGLES2 platforms
optionally enable/disable exceptions for unittest++
Unittests on by default on emscripten (may change again though)
Force exceptions on/off, must be set on cmdline when toolchain files are used