added RandomInt() function to crypto
add State.RandInt
Compile() creates a participant ordering for processing heartbeats
Add functionality to Compile()

+ iterate through ordering, process heartbeats one by one
- heartbeat processing not actually implemented
+ generate new heartbeat
+ sign generated heartbeat
rename bridge.c to erasure.c
Add entropy verification to Compile()
Create crypto.CheckKeys(), move to signatures.go
add tests for state.go
Merge branch 'compile' of github.com:DavidVorick/Sia
Fix CreatState() bug, split TestTick() into two functions
break Compile() into multiple functions
Add TestNewHeartbeat()
Add TestProcessHeartbeat, fix a related bug
add incomplete testing for Compile()
implement s.tossParticipant()
added tests for Compile(), discovered and fixed a bug as a result
Merge branch 'master' of github.com:Siacoin/Sia into compile
add tests for s.participantOrdering()
Now only one instance of Tick() can run at a time
Add MessageSender to state struct and CreateState