Dependency on KSPAPIExtensions

So if you're OK with using KSPAPIExtensions, this is the change I suggest for EPL.

This avoids having to put a module into all the parts just to receive the changed message.
I've also put in some SI formatting of values in the GUI.

This will work against the head of both PP and MFT / RF.

You'll need to update your Makefile to reference KSPAPIExtensions, not quite sure exactly how you'd like to organize that.