refractor developer-guide

* split library example module in two (inherent) parts
* addition of "tryton by library example" (1) and (2) as seperate parts
* refractoring developer guide to fit example-docs-style
hmm why?
Bullets are "-", "*" or "+" (http://docutils.sourceforge.net/docs/user/rst/quickref.html)
i can change for - if you want though.. i dont know if indentation works like this, but.. i dont know :)