[development] Strip out theme functions into a .theme file

[Nick Wilson]

* and then Frando (Franz Heinzmann) declared....
> * Seperation of code and design has always been a main target. So I think it's only 
> logical to stick to this policy here and move the V part of a module into a different 
> file than the C part (according to the MVC pattern)

Just getting developers to make sure tables and other html elements have
unique id's or classes would be wonderful -- im all for this, but i
think it would be beneficial if some of the theming functions *required*
these optional attributes. 

-- 
Nick Wilson
http://performancing.com/user/1