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.
This is a very bulky way of doing this, and doesn't seem sustainable to
implement every shorthand property this way, but it's a place to start.
The "margin" CSS property now expands into its four longhands as far as
my understanding of the specs.
Note that shorthand expansion happens when we *resolve* style, not when
we parse CSS. I'm not sure this is correct anymore, I think other UA's
may actually expand shorthands into the declaration directly at parse
these days. If so, we should do this at parsing as well.
It should be possible for the CSS parser to fail, and we'll know it
failed if it returns nullptr. Returning RefPtr's makes it actually
possible to return nullptr. :^)
