Thanks to hawkee for the tip.

Conflicts:
	sass/converse.scss

Set immediate to true when calling _.debounce

When clicking on restore button for a minimized chat, the page's hash will change to `#`. It may cause problems for web apps that listen to changes in page's hash.

When `immediate` argument of `debounce` function is not set, `ev` is null and ev.preventDefault() will not be called.

Always show pending/requesting users in roster

Even if show_only_online_users or hide_offline_users
are set, show users that are pending or requesting

Also, in Makefile, remove old HTML build first during "make html" step.