Separation project for the NET and GamerServices namespaces

All .NET and .GamerServices files and references moved to new .NET libraries for all platforms

Fully tested on all platforms
Issues logged for code comments:
* #2510 Android platform calls Net.Session.Exit in AndroidGamePlatform.cs
* #2511 OpenTKGamePlatform has been updated and calls Net.Session.Exit
* #2512 iOS platform calls Guide.Initialise in iOSGamePlatform.cs
* #2513 PSM platform calls Net.Session.Exit in PSSGamePlatform.cs

.gitignore updated to ignore the new .NET .csproj files
GUID generated for new projects

Took slightly longer than anticipated as some recent PR's must have added new items.  
Windows Phone is a concern because there is no Lidgren library for Windows Phone in third Party libs, so NET domain excluded and come of GamerServices that depend on NET.
There was a lot of tidy up with WindowsPhone as most GamerServices files were excluded for some unexplained reason, considered dropping NET dll from phone completely.  Instead it has most of the lib except NET for now.  Will need revisiting.