Installer fixes needed for FW8.1.0

Completes the EC Converters upgrade from Bob Eaton (LT-15663)
Removed some extra Paratext files that are not yet relevant. (LT-15654)
Changed to use .X.manifest to solve XP installation. (Damien)

Change-Id: I106dee4243e4e1a78433ae53075add0dd1e8e243