Merge branch 'master' of git://github.com/mozilla/addon-sdk into 866532v2
Revert "Merge pull request #1018 from erikvold/866532v2"

This reverts commit 6faf1d06dc0ede94c9bfcc38858b1889d5ec7233, reversing
changes made to 0b52abe6a7f57f387459a2ac7cc62f5dcb70c947.
Bug 866532: expose prePath property on URL instances and making URL properties writable a=@gozala r=@erikvold