Improve README.md

Add VoMP to list of new technologies

Add links to new Wiki Technology Roadmap pages for key technologies

Simplify contributor agreement PDF download links

Add link to SPI page on Wiki
Define bcmp() using memcmp() on systems lacking native bcmp()

See 1e61e7a02f19c405a1ef9061a0d3c9eb40d65f35 for equivalent changes
for bzero() and bcopy()
Fix bug in new bcmp() function

Was revealed by ndk-build, ie, on a system with HAVE_BCMP false
reverse change that broke android compilation.
Don't send broadcast payloads on interfaces with no neighbours
Fix broken links in README.md
Wait for servald daemon to enter main loop for more reliable tests
Improve accuracy of routing print output
Make sure audio clock doesn't jump back due to out of order packets
Allow mdp ping to flood packets rapidly
Improve configuration documentation
Add stub functions for retransmission / throttling
Add packet retransmissions due to missed ack's
Resend last ACK if it is explicitly NACKed
Mark resent packets so they can be dropped
Don't ack if we aren't being used in a route
Add support for retransmitting broadcast mdp packets
Log decision when duplicates are processed
Adjust packet format for better duplicate detection
Squelch warning when we have no peers