refactor `ToHtml` instances
fix outdated doc, HtmlT builder function takes only one argument now
clean up HtmlT instances
refactor `makeElement` and `makeElementNoEnd`. Optimize HTML tags with `Blaze.fromChar`. Remove `encode` and `encodeLazyText`.
don't benchmark serialization of `Builder` to `ByteString` in \'HtmlT\' benchmarks. The efficient construction of `Builder` via `HtmlT` combinators should be tested instead.
write `TermRaw` instances in terms of `Term`
optimize `With` instances
specialize `Term` instances