Merge pull request #2 from qwertie/master

3 small changes
Edited project to compile in VS2010; stopped defining NotifyCollectionChangedAction and NotifyCollectionChangedEventHandler in .NET 3.5; signed the Theraot.Core assembly
Fix for FolderEnumeration

Getting files recursively did not include files from the passed folder
TODO: aggregate exceptions
Merge remote-tracking branch 'origin/Develop'

* origin/Develop:
  Fix for FolderEnumeration
  Edited project to compile in VS2010; stopped defining NotifyCollectionChangedAction and NotifyCollectionChangedEventHandler in .NET 3.5; signed the Theraot.Core assembly
Fixed BeforeFirst

BeforeFirst was behaving like BeforeEach
Fixed AfterLast to only work when there are items

Also added Before, After and AfterCounted to be executed regardless of
the presence of items.
Embrace WindowsBase

As per qwerties's modifications WindowsBase is a dependency of
Theraot.Core on .NET 3.0 and above. Theraot.Core shall not cause
conflict with WindowsBase.
Rebuild SharedTemplates (and clean up)

The new SharedTemplates does not require Theraot.Core to run.
Rename INotifyCollectionChanged.net35.cs to INotifyCollectionChanged.net30.cs
Rename NotifyCollectionChangedAction.net35.cs to NotifyCollectionChangedAction.net30.cs
Rename NotifyCollectionChangedEventArgs.net35.cs to NotifyCollectionChangedEventArgs.net30.cs
Rename NotifyCollectionChangedEventHandler.net35.cs to NotifyCollectionChangedEventHandler.net30.cs
Updated project to recent renames
Clean ups and fixes from code analysis
Merge remote-tracking branch 'origin/Develop'

* origin/Develop:
  Clean ups and fixes from code analysis
  Updated project to recent renames
  Rename NotifyCollectionChangedEventHandler.net35.cs to NotifyCollectionChangedEventHandler.net30.cs
  Rename NotifyCollectionChangedEventArgs.net35.cs to NotifyCollectionChangedEventArgs.net30.cs
  Rename NotifyCollectionChangedAction.net35.cs to NotifyCollectionChangedAction.net30.cs
  Rename INotifyCollectionChanged.net35.cs to INotifyCollectionChanged.net30.cs
  Rebuild SharedTemplates (and clean up)
  Embrace WindowsBase
  Fixed AfterLast to only work when there are items
  Fixed BeforeFirst
Fix for Linq's Single and SingleOrDefault
Improved exceptions on SemaphoreSlim constructor
Made IExtendedGrouping variant when it can be
Updated Readme
Updated Reame (fix)