Remove SteveSoft Regex as a dependency

I don't doubt that there was a fine reason to use stevesoft Regex. But for simple operations, we should be able to use the native Java and JavaScript Regex.

The problem is that this package adds 80+ classes and over 300K of code. It can't be necessary, in general.

I propose reviewing the uses of that package case by case, starting with the most common (Newick, perhaps) and eventually abandoning that altogether. SwingJS uses Regex very efficiently, leveraging the native JavaScript version for no-load Regex processing. I suppose there are a few obscure differences between Java and JavaScript Regex, but they must be quite obscure.