Update loadMemberGroups.cs

Sort the roles alphabetically to make it easier to manage the list when it becomes very large.
v7 NuGet changes also apply to v6
Make sure the App_Plugins folder is there
Forgot a few includes, fixed!
Merge branch 'patch-1' of https://github.com/designagencytom/Umbraco-CMS into designagencytom-patch-1
Merge branch 'patch-2' of https://github.com/designagencytom/Umbraco-CMS into designagencytom-patch-2

Conflicts:
	src/Umbraco.Web/umbraco.presentation/umbraco/members/EditMember.aspx.cs
Merge remote-tracking branch 'origin/6.2.0' into 7.1.0

Conflicts:
	build/NuSpecs/build/net40/UmbracoCms.targets
	build/NuSpecs/build/net45/UmbracoCms.targets
	build/NuSpecs/build/net451/UmbracoCms.targets
	build/NuSpecs/tools/Readme.txt
	build/NuSpecs/tools/install.ps1
	src/Umbraco.Web/umbraco.presentation/umbraco/members/EditMember.aspx.cs
Adds better error handling for the media picker - we were not detecting image types before and were getting loads of server errors. Fixes up some method return calls
Fixes: U4-4502 Umbraco7.0.4 media picker shows uploaded images minus 1