Fix bug where regexes are matched as strings when 'required'

[cogwirrel]

When a regex in a mapping is required, it would get matched as a string rather than a regex.

This pull request fixes that issue.

See the success test for the case that would previously fail.

[coveralls]

Coverage increased (+0.1%) to 87.652% when pulling 459204f on cogwirrel:unstable into 2c8e3c0 on Grokzen:unstable.

[Grokzen]

@cogwirrel Nice find, good test cases and good implementation. The only thing i am missing for this one is a line in docs/release-notes.rst and if you want, add yourself to docs/authors.rst and this should be mergable.

[cogwirrel]

@Grokzen Thanks! Updated those files.

[coveralls]

Coverage increased (+0.1%) to 87.652% when pulling 068183d on cogwirrel:unstable into 2c8e3c0 on Grokzen:unstable.

[Grokzen]

@cogwirrel Awesome. Thanks for the fix.