Remove unused `path` args from list_env, Fixes #4847
result should be True if already configured
Add logs to know what's happening in `salt.utils.which`

* Move logging initialization to the module scope since there's no problem with that now.
* Switch double to single quotes.
Fix #4913
Properly pass cwd, runas, and shell through in _run_check(), Fixes #4825
Remove un-used `message` arg, Fixes #4824

Don't know where it came from, but `ret` contains all the message we
need
Remove `user` arg from ssh.recv_known_host.  Fixes #4822
Fix some pep8
#4822 errata: update the docstring example too
updated suse package for 0.15.1 release
updated salt.changes file
Fix scheduler for the minion, Fix #4937
use sets for platform tests for enabling/disabling modules
harmonize at.BAD & system.UNSUPPORTED => disable

Conflicts:
	salt/modules/at.py
	salt/modules/system.py
fix "minon" misspelling; format example bash command
fix some Sphinx warnings
Only import pwd in one place, Fixes #4808

Also make it so windows minions can import master.py without barfing on
the original pwd import
Small copyedit and pep8 fix
Use salt.utils.is_windows()
Fix some pep8