Add decorator for matching regular expressions

[grantbacon]

Introduces a decorator similar to @triggered--named @regex_triggered--which returns a command if any of the provided regular expression patterns match the message text

[Era-Dorta]

This looks great, thanks a lot. It is a feature that should have been implemented long ago.

[Era-Dorta]

I missed the comments in the my previous review, sorry.

[grantbacon]

It would be nice to be able to access re.Match objects returned by re.search() in Command#handle() but I'm not sure the least disruptive way to make that change. Can always call re.search() again to get the matches I suppose

[Era-Dorta]

Thanks a lot for the fixes, if you don't mind, I have a few more minor comments. Regarding the re.Match objects, I agree, I don't think there is a neat way to return them and pattern matching is quite fast, so I'm inclined to leave as it is for now.

[grantbacon]

Cool! I think I've addressed all the review-- let me know if any other changes to be made, thanks again for taking a look at my changes

[Era-Dorta]

Very happy with the last set of changes, thanks!