Add support for per-tile minimap color and height/ramp type.
TileSet cleanups.
Rename TileTemplate -> TerrainTemplateInfo.
Load tmp(ts) ExtraData for cliffs etc.
Work around the undesired R8 terrain sprite offsets.
Convert TS terrain height, ramp, and minimap colors.
Introduce TerrainTemplatePreviewWidget.
Moves a few start location/spawn traits to Mods.Common.
Adds Mods.Common usings where necessary.
Reimplemented TraitsInConstructOrder()
Added missing trait dependency
Move Power and PowerdownIndicator effect to Mods.Common
Prevent crash dialog from popping up when the game restarts

Fixes #6887
Add Angusm3 to AUTHORS
also measure render performance bottle necks

closes #4133
Add System.Core reference to OpenRA.Mods.Common.csproj for Linq
Moves the remaining two ServerTraits and 3 out of 4 Modifiers to Mods.Common
Add country definitions
Set up custom prerequisites for FACT
Fix Parachutable to work for tank drops