Fixed the CSV paging. Maybe. Hopefully.

We're now reading in 2 pages for every page requested. We go back
byte-by-byte from the start of the requested page until we hit a
newline and trim the chunk from that point. We do the same for the end
of the chunk. This should give us consistent lines.
Fixed an issue with CSV parsing when the file didn't end with a newline.
Updated the docs for the CSV paging.
Merge branch 'dev' of github.com:iPlantCollaborativeOpenSource/Donkey into dev