Create scrollable table component

[m-j-mcdonald]

The chair views use some tables where we want the body to be scrollable and the headers to be fixed. Right now they use the hacky solution of aligning two separate tables and making one scrollable, but it should be simple enough to do a React version of this: http://stackoverflow.com/questions/673153/html-table-with-fixed-headers/25902860#25902860 and put it into its own component for reuse (as Kunal suggested on a previous PR).

One possibility would also be to incorporate this: https://facebook.github.io/fixed-data-table/
The advantage being that it would be more efficiently rendered and the disadvantage being that it might be overkill.