PCL updates:
- Add Pcl projects for all platforms
- Generator.Detect is removed for PCL build
- Rename *.Pcl.dll to *.dll, and output to BuildOutput\Pcl\$(Configuration)
- Use .NET 4.5 reflection api's, and update TypeHelper to provide needed api's for .NET 4.0 build
- Remove obsolete WeakEventHandler
- Update Eto.Json - Pcl to a PCL assembly so it can be used by Eto.Test - Pcl
- Remove CheckBox.IsChecked, and instead fix the PropertyBinding when converting to a nullable type
- Remove superfluous configurations from PCL solution files
- EmbeddedAssemblyLoader is now included directly into the assemblies that needs it (Windows, Wpf) from Source\Shared folder
- Most flags removed from OperatingSystemPlatform for PCL (e.g. IsMac/IsLinux/IsUnix/etc)
iOS: Fix Bitmap.Lock() when editing a loaded image
iOS: Fix Bitmap.Clone(). Fixes #205
Minor cleanup. Structs/ints can't be null.
Remove IGraphicsCreate code to fix compile error
Merge commit 'f81c4927c0e1a7434d95cb4295c9907027479fe7' into develop

* commit 'f81c4927c0e1a7434d95cb4295c9907027479fe7':
  Uncomment a line that was accidentally checked in commented.
  Improve BitmapSection.DrawImageToRect() test.
  Fix #189: iOS: Bug in BitmapHandler.DrawImage(graphics, source, destination). This fix uses a single code path for scaled and unscaled images, and uses clipping to ensure that only the relevant portion is rendered.
  Fix typo.
  Remove #if DESKTOP from Window.cs.
  Remove #if DESKTOP in Application.
  Test app: use feature detection rather than #if DESKTOP when creating a menu.
  Remove #if DESKTOP in Window and TreeView.
  Remove obsolete IGraphicsCreate - related code.
  Unit test fixes. Eto.Test has no associated UI, so unit tests must run without assuming the existence of an Application instance or particular widget implementations.
  Xaml: fixes for font tests. Add placeholder conversion of SystemFont to fonts. This is something that will need to be done carefully for Xaml, as there are extensive guidelines.
  Use the NuGet WinRT DatePicker package for the Xaml platform.

Conflicts:
	Source/Eto - Xaml.sln
	Source/Eto.Platform.iOS/Forms/IosWindow.cs
	Source/Eto.Test/Eto.Test/TestIcons.cs