Add flag-support to regex validators

If a Rails format-validator has rgex flags (eg /whatever/i ) it will convert
th trailing /i into flags that can be passed as a data-atribute in the
validation attributes - which can be picked up and used by your validation
javascript eg by using:

new RegExp($this.data('pattern'), $this.data('flags'))
rename flags to pattern-flags

to: a) match the pattern-message naming scheme
and b) not be so name-clashy
Merge pull request #7 from taryneast/master

Add flag-support for regexes