add version to the manifest; decouple manifest and unit inventory.
support option to skip repository synchronization.
renamed constant.
better line length.
update the dev-guide/integration.
Merge branch 'master' into nodes-skip-content-sync
pass nodes client cert text; remove unused link module.
update progress when repo sync is skipped.
add support for new error in the CLI.
Remove self.__class__ cleverness :/
Merge pull request #569 from pulp/nodes-skip-content-sync

Support passing an option to SKIP sync the repositories (content).