Add rename arg handler
Unregister event handler after docs are rendered

This fixes the case where we're generating multiple docs
in a single invocation (such as html generation).  By
unregistering the event handler, a new instance can come
along and register itself as the object to use for new doc
events.
Merge branch 'html-doc-fix' into develop

* html-doc-fix:
  Unregister event handler after docs are rendered
Add additional arg renames
Merge branch 'arg-rename-customization' into develop

* arg-rename-customization:
  Add additional arg renames
  Add rename arg handler
Remove ddb rename of scan-index-reversed
Add a doc string to all --dry-run options.
WIP commit
WIP Commit.
Merge pull request #292 from garnaat/add-dryrun-docs

Add a doc string to all --dry-run options.
New completer that is driven from the domain model rather than the low-level model.
Merge branch 'develop' into new-completer
Fixing a couple of PEP8 issues.
Fixed a Python 3.x issue.
Pull regions and output choices from JSON data.  Remove sys.exit() call.
Bumping version to 1.0.0
Merge branch 'release-1.0.0' into develop

* release-1.0.0:
  Bumping version to 1.0.0
Change dev status trove classifier to prod/stable
Change default pager from more to less
Fix a bug involving completion of preview services.  Fixes #309.