Added code that handles groups in the replace string
(for replace lib function)
Working on fixing up groups in replace
Merge branch 'master' of github.com:princjef/regex-rust
Numbered groups in replace string is working
(the lib function does have some debug prints right now)
Named groups can now be used in the replace string
Modified replace functions to return Result's
Added test cases for error return value from replace
Made tests for replacen use the Result return value