bmessage: use regex breakpoint to match category

[kastiglione]

Resolves #57

With this, commands like:

bmessage [XYZCustomView setFrame:]

Will correctly set a breakpoint on -[UIView(Geometry) setFrame:].

Updated:

This pull request now handles explicit categories on input. For example:

bmessage [XYZCustomView(Geometry) setFrame:]

Now works where previously it would not work. Additionally, if the category is given, then the breakpoint is created with the --fullname argument instead of --func-regex.

[kastiglione]

@mattjgalloway As the original author of bmessage, do you have any thoughts on this? If you're happy, I think we can merge it.

[mattjgalloway]

LGTM. Ship it!

[kastiglione]

If you insist :)