Refactor Station.id out of the class

It's not used anywhere, it is incremental, doesn't mean anything and
just adds confusion. To hell with it!
Remove incremental id from bcycle

Taken the opportunity to clean up the for mess
Remove incremental id from bicicard
Remove incremental id from bicincitta
Removes incremental id from bicipalma
Removes incremental station id from bixi

Moves all exceptions to its own ugly exceptions file
Replace pyquery for lxml in bixi

No need for it. Path is staying with just lxml