Handle discovery data for nodes via merge and overaly node-role data view [3/3]

Changed the node.discovery= function to merge data into the existing data instead of replacing it.
This change was needed so that multiple jigs could update the discovered data without stomping
on each other.  

This change was needed so that I could start working on inbound attributes (planned for Friday).

Also, added an example of the node-role edit data overlay page.  This allows developers to add 
custom screens for each role (like CB1 for proposals) instead of relying on the raw mode.

This is preliminary function but a good demonstration of the basic concept.


 .../barclamp_test/app/models/barclamp_test/jig.rb  |   32 +++++++++++++-------
 .../node_roles/_test-discovery.html.haml           |   11 +++++--
 crowbar_engine/barclamp_test/config/locales/en.yml |   14 ++++-----
 3 files changed, 36 insertions(+), 21 deletions(-)

Crowbar-Pull-ID: 4cf7281eca2d501acdae94e8a48c95d5944c55d7

Crowbar-Release: development