Feature/autoplay toggle on start

[MathEman-1]

Description

1. Alt/Option + A Start autoplay should be a toggle (start/stop depending on the state - same as the other key combination toggles)

2. Add prop/tag to Deck to pause autoplaying on slideshow start

Fixes #633 (issue)

Type of Change

Please delete options that are not relevant.

• New feature (non-breaking change which adds functionality)
• This change requires a documentation update

How Has This Been Tested?

Master branch has been downloaded and functionality has been tested by manually trying the 2 new features in the example project. To verify changes:

1. Enable autoplay in the example presentation and start/pause autoplay multiple times with key combination Alt/Option + A

2. Setup Deck props with all combinations of autoplay={true/false} and autoplayOnStart={true/false}

• Case autoplay={true} autoplayOnStart={false} -> presentation will be unpaused on start (can be paused with key combination & click)
• Case autoplay={true} autoplayOnStart={true} -> presentation will be paused on start (can be unpaused with key combination & click)
  -Case autoplay={false} autoplayOnStart={false} -> autoplay controls are not available & no autoplay
  -Case autoplay={false} autoplayOnStart={true} -> autoplay controls are not available & no autoplay (autoplayOnStart is ignored)

Checklist:

• My code follows the style guidelines of this project (I have run yarn prettier-fix && yarn lint)
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes (I have run yarn test)
• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• My changes generate no new warnings

[ebrillhart]

Hey @MathEman-1! Looks like it's failing on prettier. Try running yarn prettier-fix again and pushing back up.

[MathEman-1]

Hey @ebrillhart, there were just some empty spaces in the readme - thats pretty strict :) Seems to have passed now.

[kale-stew]

Tested these changes out and they look great! Thank you for updating the docs as well. This is a handy feature that should also close #583 when merged.

I've only got one follow up request for you @MathEman-1 - could you please add this new boolean autoplayOnStart prop to Spectacle's type definitions here in our index.d.ts? If you don't want to we can merge anyway and follow up with a PR to update these, it would just be simpler if you wrapped it into this body of work. :) Thank you!

[MathEman-1]

Hey @kale-stew, I think you mean just adding the autoplayOnStart boolean definition to the index.d.ts file - I added it now. I looked into the file but somehow forgot to add it - thanks for the reminder!