Only pull off two pixels if the taskbar is actually set to auto-hide

This fixes #567
Fixed NET45 project
EnableDWMDropShadow throws an exception when AllowsTransparency is True. Closes #588
imported source code and enough to get code compiling
removed old package
Merge pull request #573 from MahApps/taskbar-auto-hide-fix

Only pull off two pixels from the window if the taskbar is actually set to auto-hide
Changed an if statement.
Merge pull request #592 from Amrykid/drop-shadows-exception

Closes #588
removed packages.config as it's no longer necessary
enable package restore for all the demos
trashed the packages folder
Merge pull request #581 from MahApps/580-windows-shell-interop

Replacing Microsoft.Windows.Shell with our own internal implementation