Added support for streaming HTML + javascript body procs
Previously, the API for bodyscripts (e.g. template::add_body_script, template::add_event_listener, template::add_body_handler, template::add_script with the right flags) was not usable for streaming HTML pages, since the full processing of such scripts was handled in blank-master.{tcl,adp}, which is not in use for streaming HTML.
Now the function template::collect_body_scripts was added, which can be used at arbitrary time to collect the body scripts and translate those to HTML. This function can be used in streaming mode to output these function when new HTML chunks become available.