Finish release-0.0.6
Increased version number to 0.0.6-SNAPSHOT
Corrected README. it said polybuf...
Added a StateListener to listen to an engine's added states
Added a HeadListener to listen to an engine's head changes
Added a BranchListener to listen to a branch manager's branch changes
sendUpdate() can now handle a receiving engine 0, i.e. no engine is specified. In that case, no attempt to compute a known ancestor is made.
added deleteBranch()
Added a setBranchTip method while removing duplicated code that did essentially move a branch
Improved the behavior of addEngine(). I'm pretty sure the engine listing for each state was inconsistent before
Added a getBranches() method
Added getEntities() and getStates() methods
Incremented version number to 0.0.7
Finish release-0.0.7