Update Confluence weather window + Add new weather strings

Some changes that are needed to transition from the abandoned Wunderground addon to the new OpenWeatherMap addon.


The first commit adds some weather tokens needed for proper translation of forecasts provided by OpenWeatherMap

The second commit is an updated weather window for Confluence, including: 
- remove wunderground specific properties
- fix issues introduced by https://github.com/xbmc/xbmc/commit/7a0a19e16d2b9d18ba66d8049343cf45ee2a723a
- refactor all code into a single xml file
- split alerts and map views

screenshots: http://forum.xbmc.org/showthread.php?tid=207110