source overhaul (work in progress)

makes is possible to add multiple sources to a news
add javascript for source managment
add input for news sources
Fix object name
Fixes several issues

@pebeah please review so far
Several improvements

Sources without link are allowed now as well.
further improvements
missing continue added

@pebeah Can't find issues anymore. Please test and update the language
valiables. Then you can merge this :-)
Merge branch 'sourceOverhaul' of https://github.com/voolia/de.voolia.news
Added missing language variables for new source method