As suggested by Joshua, this commit adds the 2-clause BSD license as a
comment block to the top of every source file.
For the first pass, I've just added myself for simplicity. I encourage
everyone to add themselves as copyright holders of any file they've
added or modified in some significant way. If I've added myself in
error somewhere, feel free to replace it with the appropriate copyright
holder instead.
Going forward, all new source files should include a license header.
Some inline stylesheets use HTML comments like "<!--blah blah-->".
The HTML parser currently generates a comment child node of the <style>
element whenever this happens, and we don't want the comment itself to
be interpreted as part of the stylesheet.
