Added the @Graph.Helpers annotation.  #412

Still need to apply the annotation on the methods we want to protect.
Merge remote-tracking branch 'origin/master'
Update changelog.
Rename method to be consistent with StrategyGraph.
Renamed Strategy.Context to Strategy.StrategyContext in prep for a move.
Move StrategyContext to its own class.

No longer a static inner class of Strategy.
Forgot to add file on last commit.
Factored out use of Strategy.
Removed the Strategy interface...no longer needed.
Update docs around removal of Strategy interface.