Middle ground on composer & bootstrap. I'm *adding* a version of bootstrap
to the CORE repo. The composer version now installs a parallel copy
in fannie/src/javascript/composer-components. Pages will use that version
if it is present, but otherwise fail over to the copy I'm committing
here. This way developers can experiment with upgrading package versions
but end-users don't need to know about it or have an extra step in
the install process.