Beginnings of Forward Error Correction support. Protocol negotiations and ability to extract the base codec data from RFC 2198 RTP packets. Does not do anything with the redundant data, yet.

git-svn-id: svn://svn.code.sf.net/p/opalvoip/code/opal/trunk@31124 023b2edf-31b2-4de3-b41e-bca80c47788f
Merged revision(s) 31115-31124 from opal/branches/v3_12:
---------------------
r31123
Fixed including out of bounds OLC generic parameter when it has the suppress value. H.264 is not refused by some H.323 endpoints now.
---------------------
r31122
After going off hold (full TCS after TCS=0) some servers (cough Radvision cough) need us to renegotiate master/slave. Why? Who knows.
---------------------
r31121
Fixed H.323 re-opening media (sending OLC) if remote puts us on hold before we have completed the opening of the initial media channels (no OLCAck yet).


git-svn-id: svn://svn.code.sf.net/p/opalvoip/code/opal/trunk@31125 023b2edf-31b2-4de3-b41e-bca80c47788f