Ensure cores passed to docker container when running single multicore process. Fixes #20
Use host networking on docker runs to enable network access on AWS VPCs
Support for running IPython analyses inside docker: mount external directories, find reference data relative to container, correctly interact with compressed ipython messages
Fixes for biodata mounting: avoid symlinks and use data paths in configuration relative to internal docker container. Fixes for installation: avoid always running data upgrades and handle empty configuration files
Update bcbio AMI with latest docker, HVM support and SSD backing