4 - Finish all the core CSS traits
5 - Implement all non-essential attribute transforms
8 - Massive profiling, make it faster!
10 - Make URI validation routines tighter (especially mailto)
11 - Distinguish between different types of URIs, for instance, a mailto URI
12 in IMG SRC is nonsensical
13 - Factor out Host validation to its own AttrDef
14 - Rewrite table's child definition
15 - Silently drop content inbetween SCRIPT tags
18 - Do fixes for Firefox's inability to handle COL alignment props (Bug 915)
19 - Pretty-printing HTML