add config_txt_entry_search function, add comment to functions brace
this function sets defaults to txt_entry_search widget
add config_btn_search
this function sets defaults for btn_search widget
add config_btn_download
this function sets defaults to btn_download widget
add STM_NOTIMPLEMENTED_TOOLTIP_STR for inactive/insensitive widgets
add config_btn_toggle_play, fix typos
this function sets defaults for btn_toggle_play widget
add assemble_ui()
this function packages every component into a usable UI