src/{ui,components,constants}.js: Increase popup margins.
src/co{mpone,nsta}nts.js: Fix spacing between popup text and media.
src/{ui,constants}.js: Use HTML in text, use hyperlinks for glossary definitions.
src/{ui,constants}.js: Highlight About text links, move ABOUT_TEXT code.
src/constants.js: Adjust glossary term names.
src/{ui,constants}.js: Add 'What's this?' About link, remove snpRate parameter.
src/constants.js: Work on UI text: add terms, add Applications text.
src/{ui,constants,components}.js: Make applications popup work, link to it.
src/{game,simulate}.js: Enable error rate input.