Add _is_bin to namespaced functions

Fixes #5336
Add explanatory comment based on #5235
clarify that states.cmd.wait{,_call,_script} ignoring their args is OK; see #5123
Correct arg ordering in states.cmd.run() docstring
Add try/except to not fail on missing info

Fixes #5334
fix NoneType error

Check to make sure user and domain aren't None
bump windows installer version number.

0.15.3
add resource limits in salt-master.upstart to correct issuse #5323

<https://github.com/saltstack/salt/issues/5323>
Fix modules.useradd so that `home` isn't overloaded with multiple meanings
and then allow states.user to support `createhome` as an alternative to
the multiple meanings of `home`.

This also fixes the edge-case that useradd would under specific
circumstances create a home directory called "True".