Added TimeHelper class and tests.

Class to be used for simple timestamp based randomization
and still allow testing.
Modified hello thinkup insight to be random based on TimeHelper and updated tests.
Updated FrequencyInsight to use TimeHelper for randomization.
Breaking text out into text function.
Another take on the randomization and text handling.
Don't show user avatars twice when the appear in the insight header

Add ThinkUpInsightUnitTestCase::getRenderedInsightInHTML() to test
  fully rendered insights.
Add a new test for the interesting followers insight.
Remove duplicate names in the List Membership insight.
Only generate an interaction insight for more than one mention
Show the username instead of full_name when missing (InterestingFollowers)

Added test for new least likel followers.
Moved the seconds formatting function of the insight into the class.
Handle missing full_name in the _user template.