Using int was a mistake. This patch changes String, StringImpl,
StringView and StringBuilder to use size_t instead of int for lengths.
Obviously a lot of code needs to change as a result of this.
Node.normalize() is a standard DOM API that coalesces Text nodes.
To avoid clashing with that, rename it to fixup().
This patch also makes it happen automagically as part of parsing.
Instead of HtmlView clients having to worry about parsing and loading
the default CSS, just take care of it inside StyleResolver.
The default style is automatically inserted into the stylesheet list,
at the very start, so everyone else gets a chance to override it.
