Normalize license headers of the webodf.js source files

* remove @license tag (to prevent Closure compiler keeping the comment)
* use copyright@kogmbh.com email address everywhere
* remove "additional permission", to be added only to released webodf.js
* separate license header by empty line from following content
Add one special license header to the compiled webodf.js
Merge pull request #621 from kossebau/normalizeLicenseHeaders

Cleanup license headers and add only one license to compiled webodf.js