add new block to _home.html template
Merge remote-tracking branch 'origin/homepage-description-block'
Add an optional face cropping processor.

This can be used for small circular speaker images.
Show speech dates in all non-section speech views.

In a section it makes sense to not show a speech date if it matches
the date of the speech before, but when viewing a speaker or a set
of search results, the speeches are not an ordered group, so we should
show the date for every speech.