Initial Xwt Window
Add custom widget for output
More IView
Correct separator in the Menu
Exiting on closing
Beginning UI content
Fix text alignment on output
More IView, plus Handlers
Switching for the Xwt window
Fix filename dialogs to return filename instead of current folder.
Get populating the treeview working correctly.
Updating of controls are invoked to the main thread.
Merge branch 'develop' of https://github.com/mono/MonoGame into thiagoabreu-pipeline-gui

Conflicts:
	Build/Projects/Pipeline.definition
Protobuild definition for MacOS,Linux version of Pipeline tool.
Repurposed PipelineReferences.definition for the Pipeline project.
Previous PipelineReferences.definition is now Framework.Content.Pipeline.References.definition.
Remove unused using statements that caused problems cross-platform.
Moved and added missing file for Xwt project.
Added shell scripts for Mac and Linux to run Protobuild.
Changes to get Mac Pipeline project to build. Doesn't run yet, but it builds.
XS wanted to add these Info.plist files for Test and MGCB.
XS wanted to change some nodes in the Lidgren Mac project.
Refactor of WinForms mouse input to behave like XNA.
Fixed incorrect client rect test.
Fix for multi-GameWindow support.
Pipeline.Mac project builds, but doesn't launch.
App builds and kinda runs.