Create shared IPython cluster connections for full blocks of analysis to avoid multiple rounds of cluster creation/destruction. Enables better use of resources of highly used shared clusters
Removed unused import.
Merge branch 'master' of github.com:chapmanb/bcbio-nextgen
Moved downstream summarization to a separate repository.

This removes the pandas dependency and looming rpy2 dependency.
Fixes for global cluster view creation: handle cleanup of views, avoid passing view objects over wire, correctly estimate cluster resources for distributed regional jobs