[personal-api] user should now provide his personal API key

fixes by uNiversaI:

Conflicts resolved on rebase https://github.com/XBMC-Addons/weather.wunderground/commit/a2c10e704ffb5ab21e8146dc38541bbedd81506f with master:
	addon.xml
	resources/lib/wunderground.py

* fix WAIK = user input not -1 char else is invalid
- dont strip any characters from user api key else is invalid.

* fix location input in settings never become usable
- with this you can actually input new locations

* fix no base64 else user needs to encode api key
- ensure user entered api key is as user gets it from weather underground.
  Else user needs to base64 encode the api key before entering it in the
  addon.

* bump addon version and update changelog