Merge pull request #33 from traitecoevo/remove_callr

Remove all references to callr, replace with implementation

Merge pull request #27 from traitecoevo/26-Rscript

Check location of Rscript when installing dockertest command line script

Change order of dependencies (redux requires RedisAPI)

Missing dependency for RedisHeartbeat

New --version switch for easily determining verisons

Better treatment of docker machine selection

Add ids to rrqueue dependencies

Default for 'command'

Slightly safer DESCRIPTION downloading

New 'workdir' argument for tuning container working directories

Remove default argument to machine (no longer wanted)

Better guesses to a sensible machine to use

Ability to get image ids, returned on build