Re-working slide display rules to tighten the display a bit.

Signed-off-by: Matt Bernhardt <mjbernha@mit.edu>
Adjusting the slide height to 820px, to match the images generated. This might still need to be smaller depending on screen size needs.

Signed-off-by: Matt Bernhardt <mjbernha@mit.edu>
Adding -4px left margin on non-first images on slide layout2v. This should resolve #2.

Signed-off-by: Matt Bernhardt <mjbernha@mit.edu>