This Can_Find_Targetted_Migrations test needed a valid database to pass. This update ensures that the database is created with the old version 4.8 db schema.
fixed some tests
Potentially fixes U4-5069 Deadlock occurring in MemberService.GetByUsername

Conflicts:
	src/Umbraco.Web/Security/MembershipHelper.cs
Ensures no membership user writing when checking public access
ignores failing test - need stephane to look
ignores log4net tests
super quick performance win in the case where people don't pass in distinct values
Fixes: U4-5157 Membership.GetUser() causes 13 SQL queries, including duplicates
updates content xml bits so if it's called outside a web req it still executes.

Conflicts:
	src/Umbraco.Web/umbraco.presentation/content.cs
Fixes: U4-5199 Appending certain query strings to URLs cause InvalidOperationException (The UmbracoContext.Current is null)
Fixes: U4-5190 Overwrite Media File in 6.2.1 - process cannot access along with a bunch of other undisposed disposables :/
updates physical file system, now that files are being disposed of properly we don't need to delete first
Backports fix from 7 for GetDimensions call to ensure the file exists
Fixes: U4-5208 RenderActionInvoker needs to be able to run async so needs to inherit from AsyncControllerActionInvoker
Merge branch '6.2.2' into 6.2-4931
U4-4931 - also for ObjectCacheRuntime provider