Native window support

Add support for "native" windows (render external app windows given
their handle)
Merge branch 'master' of git://github.com/meekaah/SharpBlade into meekaah-master
Clean up @meekaah's code.

Fixed StyleCop violations in @meekaah's code.
Refactored native code to proper location.
Refactored existing WinAPI code to make it more manageable.
Fixed errors in code as result of above refactor.