Fixes regular expression for urls

Do not match inline data urls (was not working correctly).
Needs a rewrite, as we define the regex multiple times.
Adds hotfix for background-position-[xy] style getter

This property would not be inherit styles from parent.
Add requirement for perl 5.10

We are using some regex features that have been introduced
with perl 5.10, so require this version as a minimum.
[BUGFIX] Takes a copy of config instead of the reference