Moved odid-mp4-parser defintion of MICROS_PER_SEC out of the global namespace
Slightly improved the MP4 test logic

It now join()s the mp4 generator thread and uses slightly different
 pause/resume times.
Fixed a small bug in IsoFileContainerBox's size calculation logic

IsoFileContainerBox.update_box_fields() was calling the base
 IsoContainerBox.update_box_fields() - which assumes the standard Box header
 of 12 or 16 bytes. The IsoFileContainer doesn't have a header.

Also disabled some of the box modification debugging logic.

Added logging to the test interface to print the box size post-range and
 to print the output file size, for comparison. Sizes matched for all
 tested cases.