Randomizes starting 'Mechs and Mechwarriors.

* Check provided pilotIDs and mechIDs for existence to avoid NRE
* Introduce some amount of logging (logs into game log, [FYLS](https://github.com/janxious/BT-FYLS) highly recommended)
* Major code organization pass

Linked against BattleTech 1.3.2

1.6 compatibility and some new settings

BattleTech 1.3 compatible.

* Added `RerollRoninStats`, which will reroll stats/abilities on Ronin, base true
* Added `PilotPlanetDifficulty`, which sets the base planet difficulty to generate pilots from, base 0

Linked against BattleTech 1.4

BattleTech 1.1 compatible

1.7 compatibility