Closes #1569.

Closes #1163, #1495.

The development workflow can be used with Node 4+, not just Node 6. We
should avoid showing warnings and errors when users are installing this
package via npm/yarn.

Ref. #1729, #1743.
Closes #1725.

The development workflow can be used with Node 4+, not just Node 6. We
should avoid showing warnings and errors when users are installing this
package via npm/yarn.

Ref. #1729, #1743.
Closes #1725.

Expands the details already given by highlighting the defaults for all attributes and clarifying what's required.

more in-depth documentation of slide backgrounds #1542

readme tweaks

Closes #1073.

Auto-sliding will now use the method specified in the config if it is
a function or default to navigateNext.

When the autoSlideRight config option is active, the auto-sliding
will always navigate to the right and never down even if slides are
present there. This allows hidden "bonus slides" in presentations
which can be displayed as needed but won't show up automatically.