alxPause/alxUnpause fixes

Resubmission of audio files from Richard Ranft: Audio.cc, audio.h, audioBuffer.cc and audioFunctions.cc now contain the final pause/resume functionality that was in 3SS.

I updated the console function descriptions to reflect that the audio handle can now be a negative integer (for looping AudioAssets).

These fixes can be tested using the AudioBasicsToy found here: https://github.com/t2Dtutorials/Modules