These correspond to different VBR modes.

This avoids name clashes with the similarly named files in
libSBRdec, when building all libraries with one single
automake file.

Change-Id: If97c7482bffaab4a21cd2fb8341f2939f19d3bbd

Change-Id: I9d9ab17121e2db58f8a4ba4b40e14cab629b1a7e

Change-Id: I42a702487e6db4953dca0027710ea4fe266052fd
Also:
 - Removed dead code in several source files.
 - Minor changes in comments.
 - No functional changes. No changes in executed code.
 - Added documentation PDFs.

Fixes:
- Don't throw error for invalid bitrate but limit to functional value
- More robust ASC parsing
- More robust handling of corrupt bitstreams
- Handle multiple raw access units

Change-Id: Ib49fe2545ff4185fe924126da702fe84ac5c2d87

License boilerplate update to follow.

Change-Id: I2810460c11a58b6d148d84673cc031f3685e79b5