First pass at adding partialSum support.
doc
fixed up some string rendering issues
basic cleanup
made partialsum storage stuff compile. not sure if correct
removed brace. tests now pass, but I think we are leaking
partialsum_storage
cleanup + added the decref, so shouldn't leak memory anymore
made grad method preserve partialSum
made unit tests try different partial sums
fixed size of nv_partialsum
removed warning that we don't use partialsum
moved an assert to the last possible branch
test passes
Merge pull request #150 from lisa-lab/rebased_partialsum

Rebased partialsum