U4-516 - Fix DatePicker with time default value

Enables the standard jQuery date picker to parse the current value of
the field correctly, this prevents it from defaulting to Today and
overwriting the currently stored value.
Install a default member type during initial setup
Oops, accidentally killed creating a partial view from the backoffice as it's also using PartialViewTasks.cs (like when you create a partial view macro)
Argh, starter kit is hardcoding a content type, so I have to register the new member type with a different Id
Updated controller, more flexible, moved UmbracoProperty to Umbraco.Web.Helpers
U4-2549 - fix it differently
Merge remote-tracking branch 'origin/6.2.0' into 6.2.0
Fixes U4-1339 SurfaceController returning PartialView - cannot use ModelState - TempData merge correctly.
Creted MergeParentContextViewData filter, this is by default applied to SurfaceController's and the PartialViewMacroController. Now if you are rendering a partial view macro or a child action from a SurfaceController and are putting data into ViewData on a POST, you don't have to access the ViewData from the ParentViewContext.
Ensures the whole ancestry of view data is merged in with unit tests.
Fixes U4-2300 6.1.0: Changing a template's parent causes tree to collapse
Fixes: U4-2711 DAMP throws unknown exception on image upload with image cropper
Fixes U4-2300 6.1.0: Changing a template's parent causes tree to collapse
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.
Creating a partial view now inherits from UmbracoTemplatePage (in 6.2.0 there will be 2 snippets, one for UmbracoViewPage<dynamic>, for MVC experts and one for UmbracoTemplatePage, the default).
U4-2691 - fix issue with alt template and internal redirects
Bump version number
U4-2549 - fix issue with last chance content finder

Conflicts:
	src/Umbraco.Web/Umbraco.Web.csproj

Conflicts:
	src/Umbraco.Web/Umbraco.Web.csproj
U4-2549 - fix it differently
Fixes U4-2734 Don't set the cache references to null when disposing the UmbracoContext