Add support for destructive roles and debug mode.

This adds two related mechanisms:

* Roles can now have a destructive flag, which should be added to any
  role that will undo the effect of later noderoles if it is rerun.  The
  only user of this right now is the provisioner-os-install mode, which
  will reinstall the OS on the box if it is rerun.  BIOS and RAID roles
  will probably also need this mechanism.
* Support has been added for masking off parts of the noderole graph for
  a specific node.  This low-level mechanism (which should not be
  exposed to end users) is used to implement debug mode by constraining
  the annealer to only running nondestructive roles in Sledgehammer.

New features:

* The nodes controller grew methods for getting in to debug mode,
  getting out of debug mode, and rebooting a node via SSH.
Merge pull request #788 from cloudedge/pull-req-master-5a75eba6eb8ed557dfb21f1c50c4eef5c4188bcd

https://github.com/crowbar/barclamp-crowbar/pull/788

Merged by devtool for VictorLowther
Merge pull request #785 from VictorLowther/pull-req-master-711cb679ae93eb9648f168e599dceeeb06524c9a

https://github.com/crowbar/barclamp-crowbar/pull/785

Merged by devtool for VictorLowther
Update 100_introduction.md

Updated for v1.6. (Note: no CB changes for v1.6.1 were made)
Update localization.md

Notes formatting update.
Update bdd.md

Spelling, grammar & formatting updates. No technical content changed.
Start rework of attribs to let them be role driven.

Among the changes:

* Declare default attribs in crowbar.yml, either in a top-level attribs
  section or as part of a role.
* Enhance the attrib type finding model to allow for jig-specific
  customizations.
* Allow roles to declare that they want specific attributes.  Nothing
  uses this now, but it will wind up replacing the current attribute
  gathering logic that the jigs use.
Consolidate Crowbar documentation under the Crowbar barclamp

This commit moves all documentation from the crowbar repository
to the barclamp-crowbar repository. Since there are multiple repos
involed, it appears as a delete from crowbar, and new files in
barclamp-crowbar.
Merge pull request #792 from mikeyp-dell/pull-req-master-4575dffa56634296bb7517ba913f55767684f393

https://github.com/crowbar/barclamp-crowbar/pull/792

Merged by devtool for cloudedge
Merge pull request #791 from VictorLowther/pull-req-master-a5df278b8c055255c255e395c0bbfbf2cf28a449

Start rework of attribs to improve data isolation during annealing [1/3]
Update 1000_installing_crowbar.md

Table formatting.
Update 2500_installing_hadoop.md

Note format update.
Update barclamps.md

Formatting cleanup.
added deps and explanation of using the test framework
Update contributing.md

Fixed broken hypertext link (worked in Github's editor, but failed in the CB2 UI, and on http://www.ctrlshift.net/project/markdowneditor/).
Update contributing.md

Punctuation updates; hypertext links fixes; removed styling from table headers (per documentation guidelines); standardized note formatting.
Update core-barclamps.md

RAID barclamp renamed to Dell RAID.
Update 100_introduction.md

Grammar edits; fixed CB version number from 1.5 to 1.6.
Update 100_introduction.md

Added a missing close paren.
Update analysis.md

Moved the badge from the doc heading down to the body.