Removed `cloned_instead_of_copied` because it's included in the
`pedantic` group.

Fixes a bug where SQLite wasn't caching as desired because
`num_cpus::get().max(1)` is always (???) 1, which is likely
unintentional.

Swaps out vendored HTML-escaping code for a dependency that I imagine
has decent testing considering all of its reverse depedencies.

There were some *very* creative (and inconsistent!) ways to convert
between numeric types in here...