Add 5s timer functionality to random imgur

* Add [.] key to enable timer
* "Loading..." message turns red and italic when timer is active
* Press [.] key to disable timer.

After a bit of experimentation, 5s seemed optimal: 2 seconds would cause
the imgur api to trip if the app is used more than once at a time; 5
seconds is enough time to view the image without feeling particularly
slow.

Maximums:
 1 images in 5 seconds
3600 images in 5 minutes
43200 images in an hour
Adding config option to auto-add hashes to qdb

This should be useful for keeping track of certain massively duplicated
images.