1) Correctly unmask cursor and dispatch delta patches on successful {re,un}do.
2) Don't prompt to save twice on exit via Exit {accelerator,menu item}.
3) Fix cursor artifacts by always resetting origin point on DC whilst unmasking cursor cells.
4) Fix {re,un}do {accelerator,{menu,toolbar} item} desynchronisation with actual canvas journal undo level.
5) Remove scattered remnants of initial implementation of unimplemented italic support.
6) Replace rendering transparent cursor w/ manual blending over wx.GraphicsContext() due to canvas bitmap masking & performance degradation.
assets/text/TODO: updated.
assets/tools/{MiRCARTTo{Ansi,PngFile},SAUCETo{Ansi,MiRCART}}.py: reimplemented using Canvas{Ex,Im}portStore.
libcanvas/Canvas.py: minor cleanup.
libcanvas/CanvasExportStore.py:export{Ansi,Png}File(): merged from assets/tools/MiRCARTTo{Ansi,PngFile}.py.
libcanvas/CanvasImportStore.py:import{Ansi,Sauce}File(): merged from assets/tools/SAUCETo{Ansi,MiRCART}.py.
libcanvas/Colours.py:{AnsiBgToMiRCARTColours,AnsiFgToMiRCARTColours,AnsiFgBoldToMiRCARTColours}{}: merged from assets/tools/SAUCEToMiRCART.py.
libcanvas/Colours.py:{ColourMap{Bold,Normal}}[]: merged from assets/tools/MiRCARTToPngFile.py.
libcanvas/Colours.py: minor cleanup.
libgui/GuiCanvasInterface.py:canvas{ExportAsAnsi,Import{Ansi,Sauce}}(): implemented.
libgui/GuiFrame.py: adds CID_{EXPORT_AS_{ANSI,SAUCE},IMPORT_{ANSI,SAUCE}}.
assets/text/TODO: updated.
libcanvas/Canvas.py:_dispatchDeltaPatches(): handle `resize' delta patches.
libcanvas/Canvas.py:_dispatchPatch(): only commit to journal given commitUndo.
libcanvas/Canvas.py:resize(): commit `resize' & {deleted,added} cell deltas to journal.
libcanvas/Canvas.py: minor cleanup.
libcanvas/Canvas{Backend,{Export,Import}Store,Journal}.py: minor cleanup.
assets/text/arab-puke.txt: added from mircart/pack2/.
assets/text/TODO: updated.