Upgraded TextEditor project to Visual Studio 2012.
Allow TextEditorControlBase.Document to be changed.

The Document property of the TextEditorControlBase has a public setter, but the text editor did not expect a change of the current document. All references to the current document have been verified a new event has been added which is used to change the current document throughout the editor.
Added support for a hatching brush for text markers.
Allow text markers to be extended to the border of the editor.

Text markers can now take a flag that extends them to the end of the editor. When the marker includes the line ending (so line length + 1), the width of the marker is changed from WideSpaceWidth to the far right border of the text editor.