Merge pull request #62 from MOARdV/master

MechJebRPM new features
Extend needsElectricCharge to all actions.
...That was incorrect.
Ah, there we go.
Actually...
Flip the sign on TARGETDISTANCEZ

It gives +Z values to targets ahead of the ship.
Add the first JSIInternalRPMButtons element.

Button to clear all maneuver nodes.