Issue 1588 Improve Made The List insights. Adds list word frequency counts

Hey Gina, 
                 I've completed the improvements on the "Made the List" insight. I've added the functionality to  count the frequency of the words in the list titles. I have then added the top 4 words to the insight for the user to read. Is there any changes you would like me to make or are you happy with these improvements ? 

Thanks,
Gareth