adaptive-fec: initial commit

Just boilerplate text, makefile, readme.md, etc.

Nothing to see, move along.
added a rough outline.

TODO: copy stuff from paper and make refs to FEC-RTP payload/framework
RFCs
intro done.
more on the concept.
added FEC scheme
added applicability statement.
FEC post-repair feedback.
fec-cc state transitions
EITICT broiler plate.
adding edge conditions

these are based on the conditions discussed in the paper.
pre-final draft.
added Security Considerations.
Figure: interaction of RTP and FEC
added FEC framework
sending rate --> transmission rate
final submitted.
ietf90: adaptive fec slideset
IETF90 slides
updated README.d