Investigate 3D expression grid (part of the Allen API)

[jankrepl]

trafficstars

Might be actually really useful (potentially simplifying our pipelines).

http://help.brain-map.org/display/api/Downloading+3-D+Expression+Grid+Data

TODO:

• [ ] Can one choose the resolution or is it fixed to 200 microns?
• [ ] How to read it in Python?
• [ ] Is the volume "synchronized"?
• [ ] Can we reproduce these volumes with our current pipelines?
• [ ] What kind of processing do they apply to these volumes?