Feature/add people tool

This includes changes for displaying member count for each section, on the page that displays the list of sections. The UI has also been modified to reflect the count.(As of now all the enrollees will be displayed. If there are people having 2 roles within a section, they will be counted separately. If it's determined that this needs to change, additional filters could be applied, but the  base method would still remain the same)
Aha - I hadn't noticed that line in the docs (or if I had I'd forgotten about it).

This is largely irrelevant to this pull request, since we should probably just put a get_count method into the SDK, but Carter and I were talking earlier and you could still do the fast check in most cases and only fall back on the linear count in the worst case. If you were to load the first page, you could look at three possible cases:
 - There's no 'next' link, in which case there's only one page;
 - There's a 'last' link, in which case you fetch that page and get the count with two pages;
 - There's a 'next' link but no 'last' link, in which case you know that there is more than one page, but you don't know how many. In that case you have to iterate through them all.

In any case, this feels like the kind of thing that belongs in the SDK, so don't worry about it for this sprint - what's there will get the job done just fine.