Improvements

Another batch of improvements.

* 163e1e3 removes simplejson and replaces it with json. It's [shipped](https://pypi.python.org/pypi/simplejson/) with Python 2.6+ by default.
* 9d774b4 and 9f92b3b clean up code and add some small improvements
* 9d774b4 and 56adf4a should give more information for problems such as #1851
* e8b330f strips messages that servers return, for debugging purposes. This way, content like `        ..     <html>server error here</html>` are properly stripped to `<html>server error here</html>.
* efa9ac7 adds links to Github page and troubleshooting in the left bottom. I hope this will put people in the right directions for submitting issues. Just consider it, or don't merge it :-). It looks like this:

![schermafbeelding 2014-09-03 om 15 39 10](https://cloud.githubusercontent.com/assets/815976/4134857/7cf2633a-3370-11e4-9cb7-b96657c0c2c7.png)