rename ext_link to ext_stream and clean up all the references
remove some old v2 link code
convert link_ready to link_up, is primary state interface now
fill in where/how to handle multiple handshakes, just stubs
add lob_link_lob as a simple index into a lob chain
convert lob_link junk to just lob_match, much simpler
convert lob_link junk to just lob_match, much simpler
move all handshake handling into it's own methods, allow multiple handshakes
add support for custom handshakes
also support mesh-wide custom handshakes
fix the custom handshakes
basic custom handshake test
Merge pull request #31 from telehash/exlink

Simplify link state to just exchange