Simple to use editor component (non-collab for now)

This should be the future of the editor component(s). A simple API for 3rd-party WebODF editor interested, hiding all the internal complexity, so allowing us to throw things around as we need, without breaking things too much for that 3rd-party.

`make product-wodotexteditor` will create a zip file with everything needed for the editor component. Unzipping that file and following the HOWTO should make people happy. So far I successfully managed to follow my own text in there and get happy a little :)

Fixes #295 
Partially solved #195 (besides the compilation).
Your explanation makes sense. So, that means the HOWTO document needs to be standalone, and should contain everything necessary to create a program with the wodo zip file only (as it's the only document shipped with that). This file can then duplicate some of those sections (or refer to them directly), and also includes build steps + design ideas.