Add a "manage.status" runner that gives a combined up/down report

It would be nice to get the up/down state of all salt minions in a
single command.  The current runners make it so that two commands
are needed to get this information

This adds a new "manage.status" runner that will print a report of
the up/down state in a consumable format (YAML).  It also refactors
the up() and down() runners to use a common code path
Bugfix for commit 1d5ce52

If status() returns an empty dict, up() and down() will throw
exceptions, since None is not iterable.
Merge pull request #3408 from 0xDEC0DE/develop

Add a "manage.status" runner that gives a combined up/down report