Fix #65 - Added force parameter to delete non empty buckets.

Updated gcloud python docs to reflect forced bucket deletes.
gcloud-python is not a generic Google APIs client, fixing wording.
Merge pull request #88 from rakyll/docs-gix

gcloud-python is not a generic Google APIs client
Merge pull request #73 from kleyow/force

Fix #65 - Added force parameter to delete non empty buckets.
Fix #89 - Made README more user friendly.

Focusing more on *users* of the library than *developers* of the library.