new crowbar_batch script

  crowbar batch build foo.yaml

will automatically create (if necessary), edit, and apply all proposals
described within foo.yaml.  This enables building arbitrary cloud
configurations in an entirely automated fashion, which can be very
useful for testing, building reproducible demos, and eventually maybe
even partially mimicking customer environments.
crowbar_batch: allow configurable wiping of attributes via YAML
barclamp_lib.rb: extract #debug method
crowbar_batch: add some debug
crowbar_batch: add support for crowbar batch export
crowbar_batch: use constants for alias expansion
crowbar_batch: add some TODO ideas for improvement
crowbar batch build: improve wait loop

It didn't correctly handle some states, e.g. when the proposal gets
queued.
barclamp_lib.rb: split up opt_parse into reusable chunks
barclamp_lib.rb: replace evil eval with call to lambda

AFAICS this feature supporting non-standard options is not currently
used by any script, so it should be safe to change.
crowbar_batch: add support for --include / --exclude