add explanation.
add extra param to disable location lookup in certain scenarios

for example, after pulling messages from the database, it is stupid to
reinsert their location after looking up their locations.
add AnnotationUtility

not sure if this is a good name or if these methods should be split into different classes, but... whatevs.
finish this incomplete comment. whoops.
fix typo
provide persistence and retrieval of OEmbed instances
separate the Date getter from the Ohai display date getter
oembed lookup functionality. man, did i mess up the last couple commits.
use MessageManagerSyncResponseHandler