[#533] Change paster commands docs to follow paster's conventions

In paster's documentation, a required field is shown in UPPER_CASE, and
underscores are used as word separator.

Conflicts:

	ckan/lib/cli.py
[#533] Update paster's documentation and rename its title
[#533] Remove documentation of paster rights and roles.

They don't exist anymore.
Merge branch 'release-v2.0' of github.com:okfn/ckan into release-v2.0