Check for rst2man on posix doc rendering code path

To help for distros that rename the command (ubuntu).
Updated documentation

- Added custom layout with logo and navigation links
- Corrected command sorting
- Updated description
- Normalized case / naming
Update test to reflect latest doc changes
Merge branch 'brendandixon-update-docs' into develop

Closes #277.

* brendandixon-update-docs:
  Update test to reflect latest doc changes
  Updated documentation
Fix failing integ tests from #277

Also updated the usage strings to be consistent with the
`<command> <subcommand>` changes.
Merge branch 'jamesls-rst2man-ubuntu-fix' into develop

Closes #279, fixes #216

* jamesls-rst2man-ubuntu-fix:
  Check for rst2man on posix doc rendering code path
Merge remote-tracking branch 'upstream/develop' into develop
WIP commit.
Updating a few integration tests that were looking for specific error output which has changed with new approach.