Add warning to api.

Since this endpoint doesn't currently returned structured data about the failure
we need to decide what message to show the user based on the body text of the
message. This means that changing this string in the api could cause failures.
Until this is fixed this warning will hopefully prevent changes that might have
such an effect.
Merge pull request #1455 from lliss/topic/add-warning-comment-to-api

Add warning to api.
Fixes text on account created page
Remove URL from button
Merge pull request #1454 from mtedeschi/topic/account-created-fix

Fixes text on account created page
Fix overzealous search and replace
Cache permissions
Add UDF definitions to instance adjuncts cache

This integrates the UDF cache with the instance "adjuncts" cache, which means that changes to UDF definitions will be recognized on all servers.

Fixes #1364
Invalidate cache when objects are deleted
When showing a user's own edits, don't worry about visibility

Showing a user's edits is complex because we check (for each instance, for each model) which fields the viewing user has permission to see. That results in an immense SQL statement.  But a user should be able to see all their own edits, so we can simplify that case (which is also the common case).

In addition we can simplify the giant query by excluding UDF bookkeeping fields once rather than once for each instance/model pair.
Fix lint