Improve aesthetics - whitespace

[ChrisKeefe]

Throughout the presentation, the \vspace command is used to adjust the vertical spacing of lines of text. Often, this text formatting is ugly, and frequently it is redundant or has no effect.

Acceptable PRs will improve whitespace throughout the presentation, dealing with the above issue systematically, and reducing the redundant use of /vspace. Bonus points to PRs that take a wider view, handling both text and image aesthetics.