Fixed issue #188

A route containing path params with regex is converted to regular expression by using `Matcher.appendReplacement` which has a special treatment of backslashes (\\) and dollar signs ($) in replacement string.
There is a `Matcher.quoteReplacement` method which is intended to produce a *literal* replacement string for `Matcher.appendReplacement` method.

I think using the method above would be the best and minimalistic solution for this issue to be solved.