Added alcGetContextsDevice and alcGetCurrentContext functions.
Added alcMakeContextCurrent return values.
* Spaces and indentation.
* Fixed alcGetCurrentContext.
* Added some guards.
* Added freealut testcase.
* Fixed OpenAL currentContext.
Merge pull request #1010 from azmeuk/openal

Minor OpenAL improvements.
Added "emcc" command for Windows
Added name to AUTHORS
Use .bat files to route 'python emxxx' to 'emxxx' on Windows. Remove reference to juj/vs-tool emxxx.exe in favor of the new .bat files.