Magic icons and other improvements

Many template improvements:

1. Skills now have correct governing attributes assigned.
2. Skills now have correct use values for leveling up.
3. Magic effects now belong to proper schools
4. Magic effects now have icons assigned that show in the in-game UI.
5. Main script has been fixed so it now doesn't run EnableMenus command every frame. Beside being un-optimized code, this made the UI rather unresponsive when trying to click on items.
6. Player NPC now has an empty Model/Animation field. Before it had BasicPlayer.dae assigned and nelsson mentioned it caused problems for him.

Known issues / limitations:

1. Due to how OpenMW loads icons, the magic effect icons show in-game only the popup where spell's magic effects are listed. The currently equipped spell slot in the bottom left UI remains pink. One way to fix the problem is by duplicating the magic/.. folder and its contents and naming the folder to b_magic/.. but that's a hacky way of doing it. Related issue openmw#7065 (closed)
2. Available, hard-coded, summoning magic effects are tightly connected to Morrowind IP so icons for these are not made. This isn't a problem as it'll be a while longer before any creature models are done to actually summon.

Left to do:

• Replace the few placeholder icons with proper versions
• Include .svg source file of the icons