A bit of refactoring trying to get build:all to work.. didn't

* moved the generation of the  all tasks outside of the loop, as
  that caused it to be executed for each sub gem i.e. 3 times more
  than necessary.
* some minor stuff
* no idea why, but build:all only builds the shoes gem for me,
  tried different dependency declarations didn't change... but
  then again I'm not good at rake