Rainbow Stone theme improvements

These are some points I think are worth to be reported even if they will not all be taken in account.

1. Theme colorization to avoid themes duplication (this also applies to Bootstrap themes)
2. Where are shown the "Last system notes"?
3. Remove Julien's avatar from the theme images provided (in the list of themes to choose).
4. Is there a way for users to set their own avatar?
5. how can contributors from countries with missing flags propose their countries flag? Note: for some languages nothing appears (like ES or NL).
6. I like how menus are handled in Boostrap theme, could we use the same in Rainbow?