Add a notification on comments page when promoted link is geotargeted.
Move zk auth data into KazooClient constructor.

This ensures that reconnections after lost TCP sessions are properly
authenticated.
Fix layout of geotarget-notice icon.
Revise functions to support postgres >= 9.2
Expose date as a settable item in the API

This affects both comments and submissions. The date attribute is exposed through
the API and must include the full timestamp with microseconds without a timezone,
which is implicitly UTC.
Loosen restrictions on username characters