update to Omnibus v3.1.1

Update dependencies while here.  Drop explicit branch specification
from omnibus-software dependency because master is the default.
update config for recent Omnibus changes

Drop replaces when name matches project name.  version was deprecated
in favor of default_version.
update to latest releases

Update Puppet to v3.6.2.  Update Facter to v1.7.6 (I haven't had a
chance to test Facter v2.x yet).  Update Hiera to v1.3.4.