Avoid potential race conditions.
Revert "Avoid potential race conditions." This commit was causing some of our cache unit tests to fail, so it'll need to be looked at more closely.

This reverts commit ef7f40b7ccea7e97024eb59fbd68b82ddebd15f5.
Removed 'loud' as a value for UW Spot noise_level. Fixes SPOT-1213.
Adding infrastructure for 3-legged oauth, makes it so authenticate_user can check a user in the oauth info.
Merge branch 'master' into absent_craig
It's actually the cached json at the image's spot's pk we want to delete in the case that an image is deleted, not the cache at the SpotImage's pk.