Added a licence overview script

This script has been around for a while in various incarnations, but I
think this version is the first that's ready for the repository
Use a StyledText instead of a TableViewer in the rich goal presenter

The table view is a much nicer way of presenting the context, but
unfortunately its behaviour varies too much across platforms
Suppress the rich goal presenter's caret listener during updates

This fixes a bug caused by using the wrong range data when updating the
bottom control
Always use DOTALL mode in the sentence classification regular expressions
Filter out unnecessary whitespace when creating CoqRequireGroup tags
Don't allow the auto-completion code to look past the cursor position
Bumped the version numbers to 0.4.4.2 and added a changelog entry