Merge pull request #1 from myarichuk/master

at startup of the node, commit index will have the index of last comitted entry
Introduce explicit heartbeat timeout

Will now snapshot to node unless it is confirmed by _that_ node, that we need to
Merge branch 'master' of github.com:ayende/Rachis
The state machine is responsible for knowing what is the last applied index
CommitIndex is not referencing the LastAppliedIndex
Forcing the state machine to always remember the last assigned index
AbstractRaftStateBehavior::CommitEntries() should use lastIndex for commit