First set of changes to add crunch-dispatch and compute nodes. This is not complete yet.

refs #3219
Two compute nodes work at the slurm level. Crunch-dispatch runs.

refs #3219
Compute nodes can run jobs - almost. The final arv-put --raw in the
collation step still fails (file descriptor error?).

refs #3219
Compute nodes can now run jobs. Also, small fixes all over the place.

refs #3219
Add local git repository support.

refs #3219
Merge branch 'master' into 3219-further-docker-improvements
Further changes to make pipeline running work reliably.

refs #3219
Whitespace cleanup.

refs #3219
* Add shell node to docker installation.

* Remove documentation warning about missing crunch support.

* Various small improvements

refs #3219
Merge branch 'master' into 3219-further-docker-improvements
arvdock starts 2 compute nodes, always.

refs #3219
* Update docs to reflect that crunch is now supported.

* Rename --mrproper to --deepclean

refs #3219
Merge branch 'master' into 3219-further-docker-improvements
* move the downloading of skydns and skydock from arvdock to
  build_tools/Makefile

* add echo statements to the start of build steps in
  build_tools/Makefile

refs #3219
Whitespace fixes

refs #3219
Make the build script prompt for a shell login name.

refs #3219
Make --deepclean also remove the crosbymichael/skydns and crosbymichael/skydock images.

refs #3219
Suppress warnings and spurious error messages for the clean, realclean
and deepclean targets.

refs #3219
* add argument help to build.sh

* fix clean/realclean/deepclean invocation syntax in documentation

refs #3219
Merge branch 'master' into 3219-further-docker-improvements