Initial commit for string parsing and icons

* Added initial logic for string parsing.
- Strings will be displayed in the TreeView like they are in AW now.
Topic predicates and links are now hidden from the viewer.
- Links are now stored as a property in the UserGuideLines collection.
* Added initial support for TreeView icons.  Normal informative nodes
will be an open/closed book, where link nodes will have a link icon.
- Note: This behavior doesn't mimic AW's treeview exactly. I may improve
on this icon functionality in the future to further support teleports.
* A "world_edit" icon should be displayed now in the top left corner of
the application, instead of the default WinForms icon.