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