Add a rough makefile for the documentation.
Add a doc directory with a minimal doxygen configuration.
Finish implementing the OpusTags API.
Update opusfile.h's include guard.
Don't include deps during 'make clean'.
Public header cleanups.
Use --static with pkg-config.
Implement stereo downmixing functions.
Remove libm altogether.
Fix link order and add libm to the seeking example.
Use an unprefixed include path for the opus headers.
Remove op_get_prev_page().
Remove op_read_filter() from opusfile.h.
Initial code import.