Added support for multiple instances

Now multiple instances can be used.

Important fixes and support for .mod,.xm,.s3m,.it and ogg

-Now the library doesn't crash in c# and doesn't print clear_buffer errors.
-Now the AudioStreamPlayer node is created automatically
-Added support for tracker music(.mod,.xm,.s3m) using libopenmpt.
-Now if an ogg file is passed to play_music it will be played using Godot's built in ogg support.

Updated for Godot 3.1.1

Libsoundio has been removed in favor of AudioStreamGenerator.
Method method names now use snake_case

Fixes issue mentioned bellow

0.1.1

update binaries

First release

This release works on windows(64 and 32 bits) and gnu/linux(64 bits).
Note: I found that music stops after some minutes this due to gme assigning a default length to music, should be fixed in the next release.