Remove redundant WindowButtonCommands WPF controls

One less Grid control and one less Path control in the
WindowButtonCommands' default template, the same behavior holds.
Optimizing for less WPF controls is always good.
Note: Also fixed some typos.
Use a DataTrigger instead of the Converter
Changed FrameworkElement to DependencyObject
Kill the everything marked as obsolete with :fire:
Introduce minimize and restore animations
fixes #1512 : Bad named events
Fix null access when GlowWindows are null
Merge pull request #1508 from Dotnetifier/FlyoutCloseFix

Flyout close fix
Merge pull request #1504 from mrahhal/optimize-use-of-wpf-controls

Remove redundant WindowButtonCommands WPF controls
Delete redundant Canvas

The "appbar_github" will be merged anyways with the resources from
Icons.xaml.
Merge pull request #1522 from mrahhal/mrahhal-delete-unused-resource

Delete redundant Canvas
We don't even use Json.Net
Merge pull request #1513 from MahApps/remove-obsolete

Kill the everything marked as obsolete with :fire:
Merge pull request #1518 from xxMUROxx/hotfix/NumericUpDown-EventName

NumericUpDown : Fix Badly named events
Merge pull request #1514 from AdditionalPylons/restore-minimize-animations

Introduce restore and minimize animations
Include the TabItem clode button visual directly, so we don't have to have a dependency on the icons project

Fixes #1524
Made Flyout.cs compatible with the theme XAML
Modified Flyout animation to match Windows 8 animation
Added the AnimateOpacity property
Added the Opacity animation

NOTE: code formatting changes that Visual Studio made are also 'seen' by Git.