Support Regex in syntax highlighter

[cmaughan]

Is your feature request related to a problem? Please describe.
More control required over how the syntax highlighter works

Describe the solution you'd like
The ability to use regex to specify how the syntax highlighting works.

Describe alternatives you've considered
Add more features to the existing engine.

Additional context
Need to evaluate how hard this is to do, and what the alternatives are. Would probably need to fix the threading too.