Update tools/buildtest.lisp and git_hooks/pre-commit

Adapt to webkit2 and recent SBCL
Merge remote-tracking branch 'AeroNotix/master'
README: add missing url

Accidentally removed in b36175f7f34705306aa524ee00d61b2d8f62369d
Remove duplicate definition
Move exports to definition site
Re-define enum wrappers as constants

It is unlikely that changing these after compilation
would ever be necessary or otherwise be a good idea.
Merge remote-tracking branch 'AeroNotix/master'
Flesh out the README

Add explicit dependencies and install steps.
Some minor improvements to the demo