New insight: Facebook Age Analysis

Adds DAO methods for selecting commentors and favers.
Adds new tests to plugin tests.
Add Facebook birthday permissions, handle Facebook-formatted and partial dates

Closes #1944 closes #1944 closes #2102
Twitter age insight: fix test failures
Age analysis insight: Make the headline second-person friendly
Stop auto-refreshing after adding a Twitter and Facebook account
New insight: Top Words

Added stemmer lib and stemming function to Utils.

references #2020
Testing: run top words on staging