Fixed manifest for WP8.1 template.
New Protobuild fixing WP8.1 certification and ConfigurationMapping.
Better error message on missing MGCB.exe.
Make <MonoGameContentBuilderExe> path overloadable.
Add better error message on missing/incorrect <MonoGamePlatform>.
Added <MonoGameContentBuilderExe> to all templates to hint that it can be overloaded.
Fixed bad template parameters.
Fixed non-working $targetnametoken$ template parameters.
Merge pull request #3248 from SickheadGames/templates2

Templates and Protobuild Fixes