Fix U4-2711 add Null Check to ToXMl method

Fixes Object reference not set to an instance of an object. at
umbraco.editorControls.imagecropper.DataTypeData.ToXMl(XmlDocument data)
Bump version number to 6.2.0
Moved controllers and models as per Shannon's suggestion

Added LoginStatus and updated Register
Updated to use CDF instead of <script> tags
Updated, more robust versions of the Member template/snippets
Added admin permission for change doctype action to the OOB installer
U4-2549 - fix issue with last chance content finder

Conflicts:
	src/Umbraco.Web/Umbraco.Web.csproj
updated ignore
Merge branch '6.2.0' of https://github.com/umbraco/Umbraco-CMS into 6.2.0
Fixes U4-2713 Property Editor Value Converters don't get applied to Umbraco.TypedMedia
Fixes build errors
Fixes the rest of U4-2713 Property Editor Value Converters don't get applied to Umbraco.TypedMedia
Fixes: U4-2711 DAMP throws unknown exception on image upload with image cropper
Merge branch 'U4-2711-Fix-imagecropper-ToXMl' of https://github.com/stocksr/Umbraco-CMS into stocksr-U4-2711-Fix-imagecropper-ToXMl

Conflicts:
	src/umbraco.editorControls/imagecropper/DataTypeData.cs
Fixes U4-2734 Don't set the cache references to null when disposing the UmbracoContext
Fixes: U4-2727 PluginManager's TypeList can contain duplicates - updates the locks to be upgradeable read locks, changes over all lists/collecitons to be HashSet<T> this ensures no duplicates and also improves performance.
Fixes: U4-1339 SurfaceController returning PartialView - cannot use ModelState ?
Merge remote-tracking branch 'origin/6.2.0' into 7.0.0

Conflicts:
	.gitignore
	build/Build.bat
	src/Umbraco.Core/Configuration/UmbracoVersion.cs
	src/Umbraco.Core/Models/PropertyExtensions.cs
	src/Umbraco.Core/TypeFinder.cs
	src/Umbraco.Web.UI/Umbraco.Web.UI.csproj
	src/Umbraco.Web.UI/config/ClientDependency.config
	src/Umbraco.Web/Umbraco.Web.csproj
	src/Umbraco.Web/UmbracoContext.cs