seek-h262

The license was changed from the GPLv2 to the GPLv3.

An extra audio stream synchronization method was added.

Minor feature enhancements and documentation
updates were done.

The release definition has been extended to more accurately describe the frame type. The picture_coding_extension() progressive_frame field is now application available. Missing subsequent sequence_display_extension() and sequence_scalable_extension() errors have been added.

A bug in the test/demo program was fixed. The bug
was crashing the program during error reporting.
The documentation has been further extended.