[WU] Add personal api and fix to full working condition.

This cherry picks https://github.com/XBMC-Addons/weather.wunderground/commit/a2c10e704ffb5ab21e8146dc38541bbedd81506f by @MartijnKaijser 

With the above cherry pick only conflict resolution was required when rebasing on master.

A few minor changes were required for addon to fully work again using this new method.
Finally bumped the addon version again and updated all changelogs in process to reflect all changes.

Tested against current Kodi master fully working