nerf guard tower vs. heavy armor; misc. slight

if people want to take out tanks, they should build a turret. Right now the guard tower hits as strong as a tank shell, roughly. 
Reducing advanced tower's damage vs. infantry. Its focus should be more on vehicles. It still is ok vs. infantry with spread of 6, but not supposed to be infantry killer, per se. 
Increasing inaccuracy slightly. (3 -> 5)
-reducing turretgun vs. infantry slightly