A "smart" highlight painter designed for use in RSyntaxTextArea. Adds the following features:
- Rendered highlights don't "grow" when users append text to the "end" of them. This is implemented by assuming that the highlights themselves specify their end offset as one offset "too short". This behavior is baked into various RSTA highlights (mark all, mark occurrences, etc.).
- Ability to paint a border line around highlights.
@author Robert Futrell
@version 1.0