zaproxy: Break panel icons do not resize

I'd rather open it up for comment to see if anyone else agrees first. 

One: If you're continually using them, you'd want something big you can easily click.
There's a bit of precision clicking going or a little extra care which is required
if you're clicking constantly at a high rate.

As a bonus, i've seen quite a few people starting off with zap miss them completely
because of their size and not know how to intercept. While yes, rtfm, ui that allows
you to easily infer how to use it is a good thing.

I do think burp got the right scale + having names on this one. What do people think
comparing the two?

Original issue reported on code.google.com by contact@markcunningham.ie on 2013-02-27 09:59:47