Multimedia editing features merge request

Hello, Nicolas.

I have merged with the v2.1-dev branch and ask to pull, please.

There are some issues with our code, but we believe, they are minor.
1) Version has to be controlled in the xml string files
2) 14-multimedia-editor.xml has to be translated to other languages.
3) From Reviewer we still run old CardEditor, which allows to edit cards and their tags in old style
4) New multimedia card editor does not (yet) support tags, but it is simple to integrate.
5) Of-course we need testing and so on, but already now this editor is amazingly helpful:
- translation of words to study langauges
- google image search (search for formulas, when studying chemistry)
- pronunciation in german, english and spanish
- support for color dict
- support for audio recording 
... This stuff already allows to add much more use into the cards!
:) We use it ourselves!