$plugin_set = Bio::Graphics::Browser2::PluginSet->new($config,$state,@search_path)
Initialize plugins according to the configuration, page settings and the plugin search path. Returns
an object.
$plugin_set->configure($database)
Configure the plugins given the database.
$plugin_set->annotate($segment,$feature_files,$rel2abs)
Run plugin annotations on the $segment, adding the resulting feature files to the hash ref in
$feature_files ({track_name=>$feature_list}). The $rel2abs argument holds a coordinate mapper
callback, but is currently unused.