Start of work to clean up protocol for vclocks

Rewrite the tracker specification to not require HTTP.
Adjustments for SRP

Removing references to PSK.

Giving each key its own ID.
Fix length of RW key
Generalize terminology in core

This is in preparation to split the database sync and file sync into
separate extensions that build upon the core.
Move content to appropriate extension
Work on database sync
Add get_updates message
Add section about conflicts
Add ITCs to database
Update directory extension
Add beginning of "file presence" section
File presence
Using m prefix for a message with only JSON
Remove all references to JSON but one, move wire protocol
Update core.md

I've tried to make the terminology more consistent.  Consider adding access level to your UI example.
Update core.md
Prefix core messages with "core."
Merge branch 'patch-2' of git://github.com/wilagobler/clearskies into wilagobler-patch-2

Conflicts:
	protocol/core.md
Add access levels to suggested UI
Adjust "JSON RPC" wording, since that's a thing