We merge bootstrap-responsive.css into bootsrap.css since that is
how bootstrap distributes it from this version onwards.
bootstrap.js has a lot of changes to it which completely breaks
our typeaheads and popovers, so we will have to override these
plugins with our version of these plugins. In future versions
of bootstrap when we use npm, we can just choose not to
import them.
This commit clearly shows what changes we made to the bootstrap
library for a future reference.
bootstrap-btn.css was left out since it is from version v3.1.1. We
will integrate custom changes made by us into zulip when we upgrade
to v3.x.
We have also removed our license from these files.