Rebranding cleanup

This PR doesn't include any user-visible changes; it just updates the source files so that rebuilding the distribution will produce the same HTML, CSS, and images rather than overwriting them with old content.

One note on building: a few of the JS files provided in the repo's "dist" directory appear to be more recent than what's produced by a full rebuild.  The repo's maintainer might have built the sample distribution with the more recent versions but neglected to update the source dependencies.  Until I have a chance to fix them, I've been reverting any JS files modified after building, since I don't think we want to go backwards version-wise.