fast uploads of slight modifications

[percyliang]

When we do a cl upload, we should allow an option --base <bundle> that allows us to greatly speed up uploads in case the old bundle and the new one have very similar content, kind of like what rsync does (but without replacement). For now, the two bundles would just be stored separately.

There is a Python library that could be useful here: https://pypi.python.org/pypi/pyrsync

This would be very useful when people are developing their code and making incremental changes to it.

[percyliang]

pyrsync is too slow

Tried this one:
https://pypi.python.org/pypi/python-librsync/0.1-5
This works beautifully for smallish files, but for a 80MB file, there seems to be a bug and it doesn't work...look into this more.