ToER update 2020.20

ToER 2020.20 update includes:

1. Performance improvements for longer played games when there is large number of units and buildings
2. Updated some menu icons
3. Attacking units shall now gradually rotate towards their targets when attacking instead of instantly turning to targets as it was before
4. When player has Troops selected (more than one unit), right clicking on player's unit won't cause it to be attacked. Player can still attack its own buildings as this does not interfere significantly with battle micromanagement. Also player can force-attack via Attack icon while Troops selected. Right click attack on another self-unit is also performed when only one unit is selected. Attacking other nation units is not affected by this update.