New implementation of RangeBasedAccuracy

In the model of shooting solved next tasks:
1. The game must be playable;
2. Unit always have chance to hit;
3. Unit always have chance to miss;
4. Chance to hit depend on range to target;
5. Chance to hit depend on lighting (day/night and sources of light);
6. To hit in Sectoids difficult, in large units – easily;
7. Chance to hit on range 10 tiles approximately equivalent as displayed accuracy;
8. Autoshot great only for short range (near 7 tiles);
9. If you have displayed accuracy near 120% and above, you almost always hit on any distance.