Aesthetic changes to indenting and comments

Signed-off-by: Matt Bernhardt <mjbernha@mit.edu>
Adding a 3-vertical layout to slide styles;
Starting to flesh out responsive styles

Signed-off-by: Matt Bernhardt <mjbernha@mit.edu>
Switching to L&T-style footer for better integration with Libraries' web presence;
Adding individual class names to styles, allowing for style overrides for individual slides;
Implementing slide-specific styles for half a dozen slides

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