Overhauled star placement system, added sector stats:

+ Changed method by which stars are placed, each square now has a 1/3 chance of spawning a star system.
+ Stars now have between one and ten planets, with a 50% chance for each additional planet.
+ Reduced the number of RNG calls to one for generating the number of planets in the system.
+ Subsidised route placement now adds up to half of the available routes from the chosen star in each round of route placement.
+ Interface shows stats about the sector and the empires within it when no system is selected.
+ Interface allows stars to be deselected.
+ H1 tag for the no system selected screen is now black, even after a system has been selected.