Added Razor Nested Layout failing test

Created a new unit test that fails when a given Layout has a Layout
itself.
IntroductionLayoutRazorTests.Simple_Nested_Layout_Example()
Corrected Razor Nested Layout test
Update ServiceExtensions.cs

Fix invalid Cast
Enable Service.cs to work with to work with IREDISClientsManager
Update ServiceExtensions.cs

Handle null IRedisClientsManager
#668 use extension method to create object instance
Merge pull request #708 from markwoodhall/xmlmetadata

#668 use extension method to create object instance
Merge pull request #707 from miketrebilcock/master

Enable service to work with IRedisClientsManager
Only check for IsWatchedFile if a file was found.

There are some situations where the e.FullPath filename isn't found by
the virtual file system provider (it doesn't exist, etc.) so we need to
account for that before calling views.IsWatchedFile.
Merge pull request #709 from aaronlerch/razor-fsw-fix

Only check for IsWatchedFile if a file was found.
Add LastMessageProcessed to MessageHandlerStats
Add .pdf to Config.AllowFileExtensions
Merge branch 'master' of https://github.com/ServiceStack/ServiceStack
Update express NuGet to point to Razor dir
pre-INCR to v3.9.49 - setup for vNext
Added support for Nested Razor Layouts

Updated the RazorPageResolver ResolveAndExecuteRazorPage function to
recursively render layouts until it finds one with no RazorPage Layout
value assigned.
add separate modified build-local for local CI
keep task, comment operation
Merge pull request #711 from pwhe23/master

Added support for Razor Nested Layouts
Add StripLinesAndWhitespace and convert tabs to spaces