Further powertrain tweaks for feedback from yesterday's patch.

Additions

• Added tooltips to all advanced engine design sliders.

Changes

• RPM limiter now shown in the engine RPM graph.
• Decreased throttle responsiveness, resulting in less sudden acceleration and deceleration. Stopping you shooting past the rev limiter as easily (though I'm sure the crews appreciate it too).
• Cruise control changed from steps to a continuous throttle.
• Tweaked movement info layout.

Fixes

• Improved handling of clutch braking with engine RPM limiters.
• RPM limiter now forced to be 10% above the upshift RPM. To compensate for the torque dropoff required for the limiter to function smoothly. This was causing the difficulties upshifting.
• Fixed cruise control steering not matching the current throttle level, speeding up on turns.

- Hamish