Fix docs and upgrade dependencies

• INTERNAL: Upgrade dev dependencies.
• DOCS: Fix changelog typo.

More error-handing, and `font-display` support

• BREAKING: Change to get-token() return value when the key path cannot be
  resolved, and $handle-missing-keys is unset or silent: Maps along the
  missing key path are no longer interpolated into the returned string. This
  is part of the fix for #49. Use $handle-missing-keys for more precise
  missing subkey behavior.
  (Thanks to John Crim @johncrim)
• NEW/BREAKING: Font maps accept display key,
  which can be used to set font-display property for importing web-fonts.
  (thanks to André Schließer @schliesser)
• BUGFIX (#49): Using get-token() to resolve a missing key no longer errors
  when using dart-sass and $handle-missing-keys is unset or silent.
  Instead, the unresolved path is returned.
  (Thanks to John Crim @johncrim)
• BUGFIX (#61): Using get-token() to obtain a 2nd level or deeper submap no
  longer causes a fatal error when using dart-sass and $handle-missing-keys
  is null, warn, or error.
  (Thanks to John Crim @johncrim)
• INTERNAL: Run unit tests with dart-sass (in addition to node-sass, which was
  used prior).
  (Thanks to John Crim @johncrim)
• INTERNAL: Upgrade dev dependencies.
• DOCS (#53): Use html rather than :root for examples.
• DOCS: Wrong parameter name in contrast-ratio() function docs.

Performance Improvements & Error Handling

• NEW: (#41) Global $handle-missing-keys allows you to control exactly what should happen when a key look-up fails. The default silent provides backwards-compatible silent-failure. Other options include:
  • null: get-token() will return null, similar to Sass map.get()
  • warn: get-token() will return null, and also throw a warning
  • error: get-token() will throw an error if the value is not found
• NEW: \\ (an escaped backslash) can be used to ignore (\\#not-an-alias) or end (#alias\\not-part-of-alias) a # reference
• INTERNAL: (#41) Major performance improvements to the token look-up algorithm

Huge thanks to James Camilleri (@jcamilleri13) for all the improvements here.

Fix docs and upgrade dependencies

• DOCS (#54): Fix broken links in docs
• INTERNAL: Upgrade dev dependencies.

Fix function registration with Sass modules

BUGFIX (#46): Fixes register-function() usage with Sass module syntax

Fix function registration with Sass modules

• BUGFIX (#46): Fixes register-function() usage with Sass module syntax.

Patch bugs and dependencies

• Upgrade dev dependencies.
• Core:
  • BUGFIX (#36): Fixes an issue with quote() in dart-sass.
  • BUGFIX (#38): Fixes an issue with false values in maps.

Memoization Bugfix

BUGFIX (#31): Fixes an issue with longhand map memoization

Improved Contrast & Theme Support

2.1.0 - 12/20/18

• Plugin: Color
  • NEW: contrast(), contrasted(),
    var-contrast(), and var-contrasted()
    provide access to the lowest accessible contrast value,
    as well as than the (default) maximum contrast value.
    Pass a valid contrast ratio (0-21)
    or WCAG standard (aaa, aa, aa-large)
    to set a cutoff ratio,
    and return the minimum accessible color
  • NEW: shades-of() generates a range of light and dark color-shades
    to help build accessible themes based on a few origin colors
  • NEW: stripe-colors() function and mixin
    generate a color-stops or a full striped gradient background.
    This is useful for viewing the result from shades-of()

2.1.0-beta.1 - 12/13/18

• Plugin: Color
  • NEW: var-contrast() and var-contrasted()
    provide CSS variable parallels
    to contrast() and contrasted()
  • NEW: User-defined contrast defaults
    (contrast-light and contrast-dark)
    can be defined with or without the _ private-color prefix
  • NEW: Contrast-related functions and mixins
    provide a smart second light-or-dark default option
    when only one is defined (previously an error)

Improved contrast with CSS variable support

• Plugin: Color
  • NEW: var-contrast() and var-contrasted()
    provide CSS variable parallels
    to contrast() and contrasted()
  • NEW: User-defined contrast defaults
    (contrast-light and contrast-dark)
    can be defined with or without the _ private-color prefix
  • NEW: Contrast-related functions and mixins
    provide a smart second light-or-dark default option
    when only one is defined (previously an error)