from pd-l2ork: ec0538d9729fa14f592bcfdc9ea78cc399efa645

*fixed incorrect sizing of an object that used to be valid with a number of connections greater than the new, invalid object name (including empty object) that happens upon retexting the object, as well as during undo and redo.

*fixed preset segfault when doing clear on a hubless node
*clean-up

fixed elusive problem with undo where actions did not behave properly because of failing to update canvas_undo_name

Added undo font size, overhauled font resizing logic (x/y scaling is now bound to font resizing), added zoom option (ctrl+mousewheel), minor code clean-up, dynamic font resize improvements to the tooltip system and improved tooltip arrow appearance.

removed selection from the undo queue as it precludes selecting older stuff and pasting it into new stuff (undo -> select old would purge the queue ahead of that undo, so -> redo -> paste would be impossible)

finished undo implementation, added consistency to how canvas properties window is handled in undo situations, removed debug output.

more improvements to the cut mechanism. implemented rename function (11th undo action proved unnecessary and is serviced by 10). improved logic of retexting objects so that only those that have changed trigger an undo snapshot.

added more improvements to the infinite undo and reworked existing undo actions to conform to the infinite undo model. fixed per-window undo menu updating, finalized undo actions 1,2,3,4,5,9, and 10. Still need 6,7,8 and a new action 11 (namely apply, canvas apply, to front/back, and rename). Also improved paste behavior to make it more user friendly, particularly within the context of infinite undo.

major overhaul of existing undo actions to conform to the infinite undo format, changed how undo create functions, started undo recreate, reformatted undo index, a number of minor bug fixes, implemented undo actions index 1,2,4,5, and 9 and started working on 10.

implemented first layer of infinite undo (type 8, create only, at this point in time), other undo/redo actions are currently broken until they are implemented accordingly. still need to do repointer and purge_abstraction_actions. Also fixed a small lingering bug in canvas_undo_set_create.