CB 2: Make all the things use wants-attrib for smart attribute injection. [1/8]

This pull request series switches the core Crowbar framework to be
smarter about injecting just the attributes that a role declares that
it needs, instead of just smashing everything that could be in scope
together.


 .../app/models/barclamp_crowbar/jig.rb             |  11 +-
 crowbar_framework/app/models/jig.rb                |  48 ++-
 crowbar_framework/app/models/node_role.rb          |  62 ++--
 crowbar_framework/app/models/node_role_datum.rb    |  27 ++
 .../app/models/role_require_attrib.rb              |   4 +
 crowbar_framework/app/models/snapshot.rb           | 397 ++++++++++-----------
 .../db/migrate/20120731310000_create_node_roles.rb |  19 +-
 7 files changed, 323 insertions(+), 245 deletions(-)

Crowbar-Pull-ID: dccf04341e8a02b81a47fd321efe6c0256033410

Crowbar-Release: development