remove participantIndex as a special type
Operational Quorum

To see the quorum in action, reduce the constants to something
reasonable (say QuorumSize = 4 and StepDuration = 3 seconds) and then
start a bunch of servers (./bin/server) on different ports.

There's a weird seg faulting problem and I don't know what's causing it.
blegh
big changes no promises @Luke
add some testing, fix some bugs
add testing for encoding of singed heartbeats
purge libsodium
merge master and resolve conflicts
remove libsodium submodule
Merge pull request #96 from DavidVorick/back

Remove libsodium, replace with golang standard library crypto
implement DownloadFile()