Add new "World Coordinate" types.

These types provide fixed-point representations of distances, angles,
positions, vectors, and rotations in 3d space.

WAngle (and WRot) represents 360 degrees in 1024 units.
WRange (and WPos, WVec) represents 1 cell in 1024 units.

Distance types in yaml can be written as <cell>c<subcell>, e.g. "4c512" for 4.5 cells.

OpenRA.FileFormats/OpenRA.FileFormats.csproj

@@ -132,6 +132,11 @@
     <Compile Include="Support\Timer.cs" />
     <Compile Include="Thirdparty\Random.cs" />
     <Compile Include="TypeDictionary.cs" />
+    <Compile Include="WPos.cs" />
+    <Compile Include="WVec.cs" />
+    <Compile Include="WAngle.cs" />
+    <Compile Include="WRot.cs" />
+    <Compile Include="WRange.cs" />
   </ItemGroup>
   <ItemGroup>
     <BootstrapperPackage Include="Microsoft.Net.Client.3.5">