Update v0.7

-Updated to UE4.5
-New Component based system using interfaces; now able to extend any
blueprint class to have a Hydra component and receive the HydraInterface
events! See readme or unreal thread for details.
-All events now emit a UHydraSingleController, allowing for easy probe
of additional data at the event state.
-Some compatibility may be broken, but old style C++ extension is still
possible using the old delegate (still retained). New style C++ plugin
extension leads to less code, see convenience actor for details.