Fix if-statement in readURL

called even when the current slide is the target slide.

Allow users to customise MathJax options.

Give focus to previously opened speaker notes (fixes #2229)

bring install instructions to top, as is tradition

Fix typo

The Install was waaaay at the bottom, which didn't make sense to scroll through all the detailed documentation, just to find how to get started with an install.

Fixed broken link to markdown options doc

Fixed broken link to markdown options doc

Only show resume on pause if controls enabled

add a full list of transitions to readme