Fixed up BaseDatabaseFactoryTests so that it only loads in one db factory with the correct conn strings, now we can easily override to use a custom db. Added benchmark tests for bulk inserting records for the cmsContentXml table which shows how we can improve performance quite a bit especially for larger node sets. Added more unit tests for bulk inserting and fixed it up a bit more.
Merge remote-tracking branch 'origin/6.1.4' into 6.1.4-cmsContentXml_Optimizations
Cleanup of unused using statements in a few files
U4-2543 In the back office its possible to get Response Validation errors
U4-2550 Could not load file or assembly 'HtmlAgilityPack, Version=1.4.5.0
Merge branch '6.1.4' of github.com:umbraco/Umbraco-CMS into 6.1.4
Implements the bulk insert procedure for re-populating the cmsContentXml tables, removes the need to rebuild all xml structures when sorting if in LB environments
Updated the RebuildXmlStructures method with performance improvements. Added cache checking to the GetByPublishedVersion method since published content should always be 'latest' this will speed things up tremendously if items are found there. Added 2 more performance tests which show very large perf improvements, namely the Get_All_Published_Content_Of_Type shows a 77% improvement.
Changed the logic of the GetByPublishedVersion to only return from cache if the cache item is published.
Adds unit test for U4-2556 to ensure that it is solved.
Removes all references to the legacy Document.RepublishAll and replaces it's logic with the correct logic.
Doh, missed file
Added another benchmark for removing/re-inserting records for cmsContentXml table using one transaction which again improves performance. Now have changed the rebuild xml method in the content service to : Lookup all data that it needs to insert first, then we begin a transaction and inside of the one transaction we clear the data and re-insert it so if anything fails in this process it should be rolled back.
Merge branch '6.1.4-cmsContentXml_Optimizations' into 6.1.4
Fixes an issue with WebSecurity logout
Fixes: U4-2232 UmbracoAuthorizeAttribute breaks Relfection methods - ensures that no singleton instances are passed into attributes since they only ever get created once, meaning we're left with a stale version in the attribute.
updates uri extensions + tests

Conflicts:
	src/Umbraco.Core/UriExtensions.cs
Fixes build error, streamlines all calls to validate a user for base controllers.
Makes UmbracoContext disposable and fixes the module's DisposeHttpContextItems to actual perform the disposal of each item.
Include lang files in project so they'll actually end up in the final build