.tells: changed from .mytells

.tells just shows a summary, .tells show <nick> shows tells to the
specified nick. Displays only two tells in a channel, then switches to
pm for the others. Now sorts tells by date.

Also adds the year to new tells, and assumes current tells are from 2014.

[For GCI '14](http://www.google-melange.com/gci/task/view/google/gci2014/5013190148620288)