comment out some sys_vgui calls which are _probably_ no longer necessary (plus extra comments saying as much)

update open dialog window height/width/font/fontsize for iemguis as they are resized/repositioned with the mouse

disable canvas menu options when the dialog is present. Also, change variable name "o" to something less error-prone

Give window focus when asking if we need to save before closing. Using a (possibly buggy) "restore" method instead of the more obvious "focus" method, so this needs more testing

fix iemguis and canvas scalehandle to track mouse position instead of delta-- this fixes a bug when the mouse goes below the minimum dimensions. Plus, some more cleanup of the scalehandle code

restore the ability to show multiple iemgui label handles at once, and use class instead of id to identify them

use <dialog> modal instead of javascript prompt. Also, port some changes from Vanilla to allow closing window immediately after saving

remove pdtk_check_scroll_on_motion for the time being. (Not sure it's needed, but can revisit if necessary)

removed the array listview code from g_array.c.  Seemed pretty straightforward to prune, but should probably test to make sure there aren't any obscure regressions

add boilerplate for keeping track of toplevel Pd canvases in the GUI. While the GUI knows all the open windows, it can't tell the difference between a Pd toplevel and a subpatch. I'm not sure why the difference is important, but this interface supplies that info to the GUI.