* bugfix: calling imagebrowser with relative path results in non-existing dir * cleanup: removed unneeded BIF_filelist_appenddir function * added check for valid relative base when activating imagebrowser (like in filebrowser)
* bugfix: calling imagebrowser with relative path results in non-existing dir * cleanup: removed unneeded BIF_filelist_appenddir function * added check for valid relative base when activating imagebrowser (like in filebrowser)