stop gap to fix bug with the rendering context disappearing on window close, and stray gui_canvas_getscroll calls trying to access members of the vanished Window object

try to minimize the flashing scrollbars when a canvas becomes visible. (Still getting some flashes for the loadmeter.pd patch)

kludge to account for menubar in patch height. (Might want to rethink the whole idea of menubars in patch windows...)

make the "message" prompt dialog appear in the current window, and default to the canvas id if it's a canvas. This makes it possible to send messages directly to a canvas.

add event listeners for browser window maximize, unmaximize, and resize to call gui_canvas_getscroll

use it to compare performance with the "perfect_parser", which can
decode ISO-8859-1 properly

attempt to fix the "drag" event for [draw], and make it more robust. But it still needs to be tested to make sure it interacts properly with all the other events.

*added a fallback sr in case everything else fails