Home: People invite UI fix

This branch fixes two issues:
It used to be that there were no limits on the number of people an user can invite. After this fix, the user be limited to inviting to up to 5 people. She/he will see the message "To keep the conversation close and meaningful, you can invite up to 5 people." displayed as the place holder text for the search box.
Question for @psybuzz, are users added based on the data-id that's in the DOM? I'm thinking of a senario when an user adds a person, but then removes the user from the selected list, is the person still added to the convo?

The second issue is that duplicate names are displayed when the user search for people. When a user selected a name, say 'Charles X', as one of the invitees, a subsequent search for 'Charles' will still show 'Charles X' in the dropdown of names. This push fixes that. Now the name is removed from the search results.
+1 for periods.  I remember going into the summer thinking, why all this punctuation?  This feels like writing an essay.  But coming out of a 3 month period doing these practices and habits, I really respect the decision to keep a clean, punctuated style in a codebase.  Although we aren't writing essays, it gives a sense of professionalism and builds appreciation for attending to details that matter to the maintainability of a project.

tldr: I thought periods felt really unnecessary before this summer, but have come to really enjoy putting them in.  Just wanted to share, in case you felt the same!