Fixes #4321

Fixes #4322

Merge branch 'fixes/subprocess' of https://github.com/ferringb/ansible into ferringb-fixes/subprocess

In the script action: Get around a Python bug.

Merge branch 'source_control-executable' of https://github.com/skyl/ansible into skyl-source_control-executable

Merge branch 'role_report_fix1' of https://github.com/bennojoy/ansible into bennojoy-role_report_fix1

Merge branch 'hide_skipped_hosts' of https://github.com/jsmartin/ansible into jsmartin-hide_skipped_hosts

Add fileglob Jinja2 filter. Fixes #3563

Add option 'lz4' for compression in zfs module

For defaults that are integers, enforce it for config supplied values.

If a user supplies a string in the config (rather than an int), the code
should fix that- or blow up immediately- rather than allowing that value to
work it's way down and break w/in the connection object; when that happens,
the actual error is opaque and requires pdb.set_trace() to run down.

When collecting stdout/stderr *and* feeding data into a Popen instance,
communicate() must be used to avoid a known deadlocking scenario
when data sizes cross PIPE_BUF (which can be as small as 512, although should
be much larger in practice on linux).

"make webdocs" sphinx output is now clean.  Edit passes and additional content in docs still pending.

Start of organizing variable section.  This is all still in progress and not done, need to fix links between sections and re-add see-also sections, etc, etc.