Added ability to parse wildcard '*' in customtags and customattrs

*Please note this includes the `options.relaxerror` changes referred to in my other pull request.

Added the ability to parse a wildcard in `options.customtags` and `options.customattrs` to provide a more intuitive interface. Using `app-*` was the first thing I did when installing this validator in my Gruntfile, since I use many directives all namespaced to `app`. When this didn't work, I later realised I could achieve the same thing using `app-(.*)` to be picked up by the checks. This reduces the effort in achieving that result, without any impact on backward compatibility.