+^ tile: tile the image instead of scaling (background only)
+^ minsize: minimum tile size, images are scaled to at least this size prior
+^ doing tiling (background only)
+core.set_clouds(<true/false>)
+core.set_topleft_text(text)
+core.show_keys_menu()
+core.file_open_dialog(formname,caption)
+^ shows a file open dialog
+^ formname is base name of dialog response returned in fields
+^ -if dialog was accepted "_accepted"
+^^ will be added to fieldname containing the path
+^ -if dialog was canceled "_cancelled"
+^ will be added to fieldname value is set to formname itself
+^ returns nil or selected file/folder
+core.get_screen_info()
+^ returns {
+ density = <screen density 0.75,1.0,2.0,3.0 ... (dpi)>,
+ display_width = <width of display>,
+ display_height = <height of display>,
+ window_width = <current window width>,
+ window_height = <current window height>
+ }