common.py: Clean up imports
common.py: Clean up imports

- group: builtin, external, application
- split multi-module imports to lines
- remove gzip (code is commented out)
- import pylab once

kba/ocropy,stweil/ocropy,zuphilip/ocropy,kba/ocropy,stweil/ocropy,amitdo/ocropy,tmbdev/ocropy,tmbdev/ocropy,stweil/ocropy,zuphilip/ocropy,amitdo/ocropy,amitdo/ocropy,kba/ocropy,zuphilip/ocropy,tmbdev/ocropy