Cache mouse cursors to avoid re-generating them on each setCursor()

This should improve the mouse movement, where a new mouse cursor was
created on each mouse movement with black & white pixels. It's a
regression introduced in ef4f691
(which was originally introduced to improve the mouse movement
perception in a 100Hz monitor).

This might be a possible fix for:
aseprite#2713

Update laf module

Simplify About dialog

[lua] Fix Dialog:file{ save=true } so 'save' field must be =true

Before this change if we used Dialog:file{ save=false } it would show
the save version of the dialog, which didn't make sense.

[win] Minor change to call CoInitialize()/CoUninitialize()

Fix crash adding new frames when there are tags present

Fix opening files from CLI with new OpenBatchOfFiles utility

Update laf

Fix compilation with g++

Fix Simple ink on indexed sprites when painting w/transparent index