[Inkscape-docs] keeping track of our work on the book

Howdy,

http://wiki.inkscape.org/wiki/index.php/User_Manual_Status_EN is created to help us keep track of what's happening during book sprint. Feel free to take care of the rest of the table :)

The plan for me for today/tomorrow is to finish lists of changes across versions for other tools and then to go reworking and merging that text into the manual.

By the way, later (or now? :)) we could have http://wiki.inkscape.org/wiki/index.php/User_Manual_Status_FR/RU/PT/etc. :)

Alexandre