Fix HTML5 Pattern method

It seems this commit: https://github.com/jzaefferer/jquery-validation/commit/37992c1c9e2e0be8b315ccccc2acb74863439d3e broke html5 input pattern validation.

The pattern should match the entire value of the input, not just a subset.

Using the example from http://www.w3.org/TR/html5/forms.html#the-pattern-attribute on the latest Chrome (35), the input attribute is: `pattern="[0-9][A-Z]{3}"` stated as "A part number is a digit followed by three uppercase letters".

Using native Chrome validation:
'1ABC': valid
'1ABC sdf': invalid

Using `RegExp('^(?:' + param + ')$')`
'1ABC': valid
'1ABC sdf': invalid

Using `RegExp(param)`:
'1ABC': valid
'1ABC sdf': valid (because the first part matches)

This make a lot of patterns useless, for example alpa-numeric patterns which don't allow spaces, but they will match on a single letter as valid, ignoring the rest..

Other libraries do this also like before: https://github.com/dilvie/h5Validate/blob/master/jquery.h5validate.js#L239-L241