Invalidate directory objects for root objects.

Also includes a region bugfix.

Merge remote-tracking branch 'github.com/tyson/master'
Version bump to 0.4.0
Regenerate gemspec for version 0.4.0
Updating the docs.
Merge remote-tracking branch 'origin/master'
allow to set global headers for all files
Added documentation on headers property
Merge pull request #2 from rabidpraxis/master

Allow setting headers for uploaded files
Temporary workaround for buckets with dots in their name.