Improved Interplanetary Transfers

[itchono]

This PR implements improvements to interplanetary transfers.

1. The Lambert solver now immediately returns a null solution when R1 and R2 are nearly colinear. This is to help remove the banding seen in Improve Lambert Solver Performance #3 .
2. Porkchop plots now have new time labels on them using the KSP time conversion in KSP Time Conversions, Packaging and Test Improvements #4
3. The porkchop plot demo is now interactive, and shows the trajectory beside it.
4. Hyperbolic departure trajectories have been added.

Outstanding Issues/Wants

• Currently, there is no way to specify whether time should be displayed in Kerbin or Earth time (24hr vs 6h days, 365d vs 426d years)
• There is no provision yet for selecting origin/destination planets. This should be added soon.