v1.3.0-rc30 - BREAKING changes to JSON API

• Add mode=aspectcrop to ImageResizer commands and ConstrainMode::AspectCrop to JSON API for minimally cropping to the aspect ratio described by w and h
• Fix ABI tests and improve function name reporting in said error messages
• JSON BREAKING: copy_rect_to_canvas node: .width and .height are now .w and .h
• JSON BREAKING: resample_2d node: .down_filter, up_filter, scaling_colorspace duplicate fields have been removed (they are now in .hints)
• JSON BREAKING: constrain has been refactored

New Constrain JSON

"constrain" = {
  "mode"= [constraint mode]
  "w" = unsigned integer
  "h" = unsigned integer
  "gravity" = { "percentage" = {x: float, y: float }},
  "canvas_color" = (color value)
  "hints" = {
    resample_hints
  }

// Where [constraint mode] is one of these. Use the value in serde(rename) for JSON.

#[derive(Serialize, Deserialize, Clone, PartialEq, Debug)]
pub enum ConstraintMode {
    /// Distort the image to exactly the given dimensions.
    /// If only one dimension is specified, behaves like `fit`.
    #[serde(rename = "distort")]
    Distort,
    /// Ensure the result fits within the provided dimensions. No upscaling.
    #[serde(rename = "within")]
    Within,
    /// Fit the image within the dimensions, upscaling if needed
    #[serde(rename = "fit")]
    Fit,
    /// Ensure the image is larger than the given dimensions
    #[serde(rename = "larger_than")]
    LargerThan,
    /// Crop to desired aspect ratio if image is larger than requested, then downscale. Ignores smaller images.
    /// If only one dimension is specified, behaves like `within`.
    #[serde(rename = "within_crop")]
    WithinCrop,
    /// Crop to desired aspect ratio, then downscale or upscale to fit.
    /// If only one dimension is specified, behaves like `fit`.
    #[serde(rename = "fit_crop")]
    FitCrop,
    /// Crop to desired aspect ratio, no upscaling or downscaling. If only one dimension is specified, behaves like Fit.
    #[serde(rename = "aspect_crop")]
    AspectCrop,
    /// Pad to desired aspect ratio if image is larger than requested, then downscale. Ignores smaller images.
    /// If only one dimension is specified, behaves like `within`
    #[serde(rename = "within_pad")]
    WithinPad,
    /// Pad to desired aspect ratio, then downscale or upscale to fit
    /// If only one dimension is specified, behaves like `fit`.
    #[serde(rename = "fit_pad")]
    FitPad,
}

Where [resample hints] includes

    pub sharpen_percent: Option<f32>,
    pub down_filter: Option<Filter>,
    pub up_filter: Option<Filter>,
    pub scaling_colorspace: Option<ScalingFloatspace>,
    pub background_color: Option<Color>,
    pub resample_when: Option<ResampleWhen>,
    pub sharpen_when: Option<SharpenWhen>