tweak velocity/scale/energy parameters

[aomarks]

You can currently just fly around the whole map really fast using regular thrusters. We need to tweak various parameters until it feels good.

Probably it should take a really long time to span the map using regular thrusters, otherwise there is no point using FTL. Maybe each sector should feel like a pretty large area.

Also we should think about energy use for thrusters. Maybe it should be pretty cheap since it's only useful for short distance travel (compared to FTL or using battle systems which should be expensive).

If I'm reading things right, the current parameters are:

• The galaxy has 12x12 sectors.
• Each sector is a square 10,000 meters across.
• Max acceleration is 30 m/s/s (1/tick @ 100% engine power).
• No max velocity (as long as you have energy you can keep accelerating).
• Max thrust consumes 3 energy per second (0.1/tick).
• Starting energy is 1000 units.