partially fixes #156 -- but still needs work, doesnt currently load velocities properly
added Velocities to map to vel array
added Potential -> phi mapping for gadgethdf
Merge branch 'master' into gadget_hdf_fix
Fix bug with immediate_mode where certain SubSnaps would still return IndexedSimArrays. Unify underlying caching code. Add nosetest
Optimizations to render_spherical_image
Merge branch 'master' of github.com:pynbody/pynbody
Merge pull request #169 from bwkeller/master

Add velocity vector image function and documentation
treat width keyword correctly in velocity_image
fixed bug in velocity_image that caused an error if the units were comoving
made a bridge tutorial out of the bridge docstring
changed docs_update.sh to remove testdata links
included stream mode option to velocity_image that was added in #169 and updated the tutorial example
fixed width unit handling in pynbody.stars.render and added example to pictures tutorial
changed profile tutorial, updated some other things
Fixes #170
Merge pull request #157 from pynbody/gadget_hdf_fix

fix for #156 -- support loading DM only files for gadgethdf
fixes #148
Merge branch 'master' of github.com:pynbody/pynbody
trying to get travis build