These blocks implement pen features as found in Scratch 2.0
Supporting changes include:
- `Target` is now an event emitter
- `RenderedTarget` now emits an event when it moves
- `Target` can now store arbitrary "extra" data, called "custom state"
in the code, using a `Target`'s `setCustomState` and `getCustomState`
methods. This is used to store per-target pen state without requiring
`Target` or `RenderedTarget` to know anything about the pen.
- `Cast` can now cast to an RGB color object.
- `Color` now has functions to convert between RGB and HSV, constants
for for black & white, and a `mixRgb` function to lerp between two
colors.
* Import lists and variables from SB2
* Switch to Variable and List objects
* Add Clone.lookupOrCreateVariable, Clone.getVariable, Clone.setVariable
* Add (get, set, change) variable blocks.
* Copy variables and lists on clone instantiation
* Move variable options closer to blocks
* Add list primitives
* Move variable and lists storage to `Target` instead of `Clone`
* Move _computeIndex to a Cast function
* Rename `getList` -> `getListAsString`
* Renames renames
* Remove extra check in Cast.isNaN
* Fill out color utilities
* Amend Color.decimalToHex name
* Add `Cast.toScaledRgbColor`
* Add touching color, color touching color blocks
* Fix scale of Cast.toRgbColor
* Fix format of colors to use renderer-style lists
* Update `Color.decimalToRgb`
* Lint self
