along with the actual implementation comes a first attempt to better
structure the doxygen groups. putting all the groups in a bigger one
makes it easier to reference them from the file itself, and makes the
structure clearer on the module page.
includes minor refactoring in example code and modification of how the
generic and the tinygecko specific vector.h go together (bringing it in
line with stm32/f1's memorymap.h)
