Using new file I/O ABI

Note that emscripten upstream branch implements the new asyncify implementation, expected to be faster than emterpreter one.

Now examples can be compiled by module, that's useful when compilation fails at some point

Examples categories are independent from the module they use, despite in some cases module name matches category name.

Tested on Raspberry Pi... Just note that platform is very limited by GPU...

- Renamed GetGlyphIndex() parameter
 - Review DrawTextEx() implementation
 - Review DrawTextRecEx() implementation

Actually OpenAL is not used any more, it should be using CoreAudio

Keeping original API

At least on Linux, CMake seems to add automatically
the '-rdynamic' flag. As a result, Emscripten
generates a fat HTML file that does not work.
Removing it allows HTML+JS+WASM generation.