Add jquery 1.7.2 and adapt examples externs

Add jquery and update the externs for the examples (code from @bartvde).
The lib is saved into the repository to be able to run the examples
and the check-examples target offline.
Merge pull request #341 from fredj/jquery-examples

Add jquery 1.7.2 and adapt examples externs
Add (incomplete) bootstrap.js externs
Add geolocation example