Merge pull request #14 from chapmanb/master

Merge from Brad upstream
Merge branch 'recursive_shell_expansion'
Skip queueing to get machine_info, use sinfo instead
Use switch statement to allow for additional implementations
Add docstring
Merge branch 'master' of https://github.com/chapmanb/bcbio-nextgen into chapmanb-master
Merge branch 'master' into sysinfo_from_sinfo
Generalize function name
Merge pull request #172 from mariogiov/sysinfo_from_sinfo

Get machine info from command-line tools first, else queue