Review StyleCop rules.

- Enforce SA1604 ElementDocumentationShouldHaveSummary.
- Enforce SA1629 DocumentationTextShouldEndWithAPeriod.
- Turn off some rules covered by IDExxxx rules.
- Remaining rules are treated as part of OpenRA style.

OpenRA.Mods.Cnc/FileFormats/CRC32.cs

@@ -20,7 +20,7 @@ namespace OpenRA.Mods.Cnc.FileFormats
 	public static class CRC32
 	{
 		/// <summary>
-		/// The CRC32 lookup table
+		/// The CRC32 lookup table.
 		/// </summary>
 		static readonly uint[] LookUp = new uint[256]
 		{