Wrote some stuff
More parser stuff - basically works now!
Check in working Transport Manager (UDP only).

Move transport manager over to using channels instead of callbacks.
Fix up the various bugs in the existing implementation.
Error handling is still hacky/nonexistent, so fix that up later.
Merge branch 'master' into parser

(Move master branch into parser so that we have a working transport
manager)
Commit of parser tests plus various bug fixes.
Work in progress!
Add broken parser file... todo fix
Get Params tests passing.
Move immutable test variables to package scope.
Fix SipUri parser tests.
Fix host:port tests.
Add some header block tests.

(They aren't complete, and don't all pass.)
Completed and passed all header block tests.
Add support for ToHeader tests in parser_test.go

Add the infrastructure for the tests.
No tests currently written!
Return an error on multiple to/from headers.

Disallow SIP messages with multiple to: headers or multiple from:
headers.
Ignore separator chars within quotes and <,>

Respect quote- and bracket- escaping.
Don't panic on empty header bodies.
Added all to: header unit tests.
Add from: header tests.

... by copy-pasting the 'from' tests.
I feel dirty.
Add some Contact: header tests.

Still need to add some additional tests to thoroughly test multiple contact
addresses, and also to add support for "Contact: *".
Add support for "Contact: *" in parser.

Support wildcard contact headers.
Add relevant unit tests.