added pdtk_canvas_force_getscroll function to ensure critical getscroll events are executed immediately

optimizations to the scrolling algorithm including erroneous jumps in the scrollbar when pasting/cutting/duplicating things.

streamlined selection logic and added ability for pd to recognize system-wide @pd_extra variable within the path

finished importing the remainder of new K12 module abstractions, updated GUI to reflect them, improved key press capture, reformatted GUI object menu inside K12 mode to allow for more space

reenabled checking of scrollbars after startmotion->click (will need to check for possible regressions)

fixed regression in select due to 37c0cf15 commit which made it behave inconsistently thus making it impossible for floats to be treated as symbols (in cases where first argument was a symbol). Also introduced similar fix to the route object, thus allowing for second inlet to receive either float or symbol

fixed double loadbang regression due to implementation of internal pre-loadbang mechanism for the preset engine.

fixed segfault in disis_netsend/receive just like the one in the previous commit. Also added "port" inlet to netreceive that allows on-the-fly port change.

fixed segfault with netsend/receive using tcp packets where netreceive is deleted while netreceive is connected to it (after which sending data to netreceive would result in a segfault)

fixed regression where iemgui widgets within GOP sometimes got redrawn even though that was completely unnecessary

fixed gop getrect detection for objects that have been previously relocated to allow for consistent positioning