Current Work in progress Helper classes

* Helper_File.cs handled File operations, function scope almost complete, support Windows / Windows Phone and Android at present

* Helper_Reflection.cs - just started so not much in there yet

All functions tested on supported platforms in a seperate Dev branch, so this branch just contains the classes themselves for inspection
Renamed Helper files based on feedback

Helper_File -> FileHelpers
Helper_Reflection -> ReflectionHelpers

Both flie and class names updated accordingly
Updated File helper class post feedback

* Out methods removed
* GetFilename method renamed to NormalizeFilePathSeperators

Stream functions left untouched as I need to review these against the current Android implementations
Merge branch 'develop' into develop.helperclasses
Minor patch to Windows Phone FileHelper for the FileExists method. was causing a stackoverflow due to calling itself
Merge branch 'develop' of https://github.com/mono/MonoGame into develop.helperclasses
Merged with develop

Added several new reflection methods (based on the ReflectiveReader.cs)
Merge branch 'develop' into develop.helperclasses
Merge branch 'develop' into develop.helperclasses
Merge branch 'develop.helperclasses' into developcore

Conflicts:
	MonoGame.Framework/Utilities/FileHelpers.cs
	MonoGame.Framework/Utilities/ReflectionHelpers.cs
Added PSMobile build tast.
Updated targets to clean down the obj directory before doing builds
Merge remote-tracking branch 'upstream/develop' into develop
Fixed the check for PSMobile
Corrected the PSMobile test (again)
Another fix for the default.build script
Last fix for the PSMobile test
Merge pull request #1706 from dellis1972/develop

Updated default build with PSM support
Merge branch 'develop' of https://github.com/mono/MonoGame into developcore