Renamed MetroWindowDialogExtensions to DialogManager. Those who use the extension methods correctly will not be affected.

Implemented the basic mechanics to show a dialog outside of a metro window.
Fixed the .NET 4.5 csproj file.
Fixed the height of external dialogs.
ProgressBar in the ProgressDialog uses the AccentColor by default.
Changed External Dialog methods into Extension Methods. External Dialogs use MetroWindows internally.
External dialogs fire OnShown and try to copy the dialog control's background.
Fixed the ProgressDialog's ProgressBar Foreground color when the Accent color scheme is used.
Internal dialogs can no longer be larger than their containing window. They will also have SizeToContent="Height" set.
Began implementing an event that fires when a dialog is shown/closed. Also implemented OnShown/OnClose for Simple/BaseMetroDialogs.
Initial animations support implemented.
ProgressDialog support for animations. MessageDialog support was added in the previous commit.
SimpleDialog/*Dialog support for animations.
Basic animations for external dialogs. Another revision planned.
Added support for two extra buttons in the MessageDialog along with temporarily overriding the dialog's settings.
Quick fix for the MetroDemo sample.
Added a message dialog test to the CleanWindowDemo.
Changed the settings code a little bit.
Sped up dialog animations.
Updated demo. Added a HighlightedSquareButton style to match the Windows 8 screenshots.
Merge pull request #860 from Amrykid/metrodialogs-v3

[RFC] MetroDialogs v3