No disc space on travis

[rbiswas4]

The Twinkles travis runs are failing again. It seems this is because the LSST software installs are taking up too much disc space on travis.

[heather999]

Did this get sorted out?
@jchiang87 This reminds me.. we got fairly far with setting up a Docker container for the stack - is that still useful for the travis builds?

[jchiang87]

I have no idea how to fix this on travis. If I really care about a particular build, I will restart it and half the time it will work. I think that the docker image option is the better long term solution.

Note also that we can build on Jenkins:

http://srs.slac.stanford.edu/hudson/view/LSST/

I've been triggering those by hand since initially Jenkins wants to build every branch (there's a way to filter by branch name, but we have no naming convention), so I've been hoping we can get around to deleting merged branches.