initial commit. [from memory, so unreliable]: features added:
* shows SMA in table
* shows OPeriod in table
* supports arbitrary FOVs (through Scanners)
* supports scanners (see scanners.txt for what keyword to type in)
* planets.txt is tab formatted, imports nicely, ignores comments
* planets.txt includes Earth and Moon, for testing
* scanners.txt
* support for SCANsat scanners: RADAR, SAR, Multi
* support for Kethane scanners: Compact, Medium
* explain both minimum and maximum altitude causes
* ...