Implementing https rewrite support

I have implemented a https-rewrite support using the rewrite-rules from https-everywere. related with the issue #71.

I have tested the rules a little bit, and it look like that all is working.

I'm not sure about the licencing of the rules. I have fetched the rules from https://github.com/EFForg/https-
everywhere/tree/master/src/chrome/content/rules, looking at https://github.com/EFForg/https-everywhere/blob/master/LICENSE.txt show that all files (including the rules) are licenced under GPLv3+. I'm not sure, how to declare that correct.

in future, it would be usefull to add a git submodule to include the current rules. But for that, it is required to extract the rules into a different repository