Editor draft updated

Hello,

I have updated the Use Cases section of the Geolocation API editor
draft to reflect the feedback I received over the past two weeks.

http://dev.w3.org/geo/api/spec-source.html

Please let me know if you have further suggestions. Next week I will
start adding a skeleton API that should already cover some of the
issues we have discussed in the other threads.

All the best,
Andrei