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)
Now Transaction::commit() will regenerate mask boundaries
automatically if in the middle of the transaction the document
selection was modified. This is the first step to finally remove
update_screen_for_document() and any kind of manual screen
refresh.
This will be useful for scripting functions that modify the selection
too, because we wouldn't need to regenerate the selection boundaries
automatically from the script or from app.refresh() Lua function.
Related to #378