Creep: added Ogg Vorbis support

Also, modified samples reading so that it doesn't assume 16-bit PCM. Currently it allegedly supports 8-bit, 16-bit, 32-bit and 64-bit PCM integers, as well as 32-bit and 64-bit IeeeFloats, if I got the formats right.
Also, modified the pipeline so that the track is always loaded to in-memory wave stream before starting loop detection. It's more of a hacky workaround due to samples reader throwing end of stream exception for whatever reason (despite debug state indicating the OGG has only started). If someone knows the possible cause, please let me know. ^^"
Creep: added Enter and Delete keyboard controls to main playlist

Now it's possible to play the selected track by pressing "Enter", as long as it's the only one.
Also, it's possible to remove one or more selected tracks from playlist by pressing "Delete".