Fixes issue #18 along with side-effects: accidental double-clicks on checkbox and that nasty cell border.
Use the SecurityCritical attribute instead of SecurityPermission
Use constants provided by NGit instead of hard-coded strings
Update ngit submodule
Initial diff margin
Remove unnecessary or misleading comments
Remove comments from old (removed) command
Fix spelling of property
Use the ITextDocumentFactoryService to get the ITextDocument for the ITextBuffer
Ignore case when checking the margin name
Use text in buffer instead of text on disk for current text of diff
Include the encoding preamble (byte order mark for Unicode encodings) in the diff operation
Properly use Git's core.autocrlf configuration setting for diffs
Move the diff margin to the right of the spacer margin
Added editor format definitions for user customization of colors in the diff margin
Use thin rectangles in the diff margin that match the ones use for tracking changes in the spacer margin
Use the IEditorFormatMapService to provide the correct brushes for the diff margin
Validate arguments
Add stub handlers for options and layout changed
Only show the margin if the selection margin is enabled