mp4 mux: remove fixed parameters
mp4 mux: use block_t
mp4 mux: simplify box*new
mp4 mux: cosmetics

no functional changes
mp4 mux: simplify
mp4 mux: merge box_fix call into box_gather
mp4 mux: generate constant frame rate files
mp4 mux: avoid unnecessary conversion
mp4 mux: use a variable to make the code shorter
mp4 mux: simplify stts box creation
mp4 mux: c99
mp4 mux: use CLOCK_FREQ
ios2: clean opengl buffers only in active state

Signed-off-by: Felix Paul Kühne <fkuehne@videolan.org>