Also we've restored the default algorithm to bilinear + mipmapping,
which was the default on the Aseprite before we switched to Skia m96.
This was requested by some users.
Each ui::Window now can have a related native os::Window. This
connection is done through the ui::Display class added recently in
c3d52f0bbe5242923c9e38495e1be1135ca0934f.
In this way we always have an empty tile available in the drawing
process. We've also added the Tileset::firstVisibleIndex field to
change the visible index of the tile 1 so we can offset the visible
number by the user (just as a visual aid / simulate old tilesets with
index=0=non-empty tile).
Now on Windows it's more clear the different APIs to use (Windows
Pointer vs Wintab), the Wintab API works as before (generates mouse
events on WM_MOUSE message instead for each packet), and there is a
new Wintab mode to create events directly from packets (still a little
buggy with some tablets, but might be useful in other tablets to get
more precision for fast strokes).
Now we have one "auto select layer" option for the quick mode of Move
tool (Ctrl/Cmd key, true by default) an other option for the regular
Move tool mode (false by default).
This is the first commit with a simple tilemap editor. Still buggy but
functional in several ways. Several changes were made:
* NewLayer command can receive a tilemap=true to create a new tilemap
layer
* New ToggleTilesMode command added to switch between the palette and
the tileset in the ColorBar (the ColorBar was expanded to show
colors or tilesets with a generic AbstractPaletteViewAdapter)
* All commands to create new layers were moved to Layer >
New... submenu
* There are a new tileset chunk to save tilesets in .aseprite files,
and a new kind of cels to save tilemaps
* Added doc::LayerTilemap, doc::Tileset, etc. and several other types
to handle tilesets/tilemaps in the doc layer.
* Added doc::Grid class with grid specifications that indicates how a
tilemap <-> tileset must be drawn
* Added and expanded cel operations to work with tilemaps and
conversions between regular LayerImage cels <-> LayerTilemap cels
(e.g. copy cels in the timeline between layer types)
