add vpc support
set connection state ~atomically, preventing race condition in setup threads
add node core and memory amounts in slurm.conf, so we can use select/cons_res
gracefully handle vpcs, subnets with no Name tag
Allow IAM instance profiles to be passed through input configuration, enables association of IAM roles with clusters to avoid passing credentials
add vpc support
set connection state ~atomically, preventing race condition in setup threads
have slurm schedule cores as consumable resources, not just memory
not quite finished support for fetching hostkeys from launched instances
sync with upstream/master
move this to a branch

Revert "not quite finished support for fetching hostkeys from launched instances"

This reverts commit 6b17dd7847b7a58e439311fd58cec08b7b053eb9.
calculate aws key fingerprints the same way aws does
calculate aws key fingerprints the same way aws does
slurmctld will get node core counts, memory amounts from the nodes
EC2: support customization of mounted root volume (size, storage type, iops)
Make novaclient a soft requirement for use AWS/GCE use without OpenStack
need to define core counts and memory amounts in slurm.conf

https://github.com/gc3-uzh-ch/elasticluster/pull/120
Support for specifying placement groups, enabling low-latency networking between cluster instances
Merge with jwm/bcbio