Fix commans in regexp

This patch is intended to solve issue #2 that prevented regexps from having a comma or parentheses in them.

I had to do a small conceptual change: Instead of using `explode` to extract the comma delimited parameters, I am passing anything inside the parentheses directly to the rule handler, as a string. 

Then, the few rules that do need several arguments, like `in`, `between`, `property` and `method` simply explode it themselves.