Update docs and make writes unacknowledged.

Saving profile data is fire and forget, we'll use that as a default
for now.
Update include file to use library code.
Namespace constant.

Its quite likely that another application may use `ROOT_DIR`
namespace our constants to reduce the chances of an overlap.
Only load twig when its necessary.

Since we're using the bootstrap.php when saving profile data, we want to
load as little code as possible. Don't load Twig until its required.
Fix header file.

I suck at paths :(