Added snaring info, tweaked some colors and CSS
minor tweaks to wording, minor refactoring
refactored titles and descriptions

Now they're part of each level's data, added by the build system.
They're in a new partless "type=meta" cluster in the graf model. They
render correctly, but they're not editable yet.
(Also got rid of some file-level editing buttons in the non-edit
screens, so the play screen is cleaner.)