Dart-sass

* Fix a bug where loading the same stylesheet from two different import paths
could cause its imports to fail to resolve.

* Properly escape U+001F INFORMATION SEPARATOR ONE in unquoted strings.

Command-Line Interface

* Don't crash when using `debug` in a stylesheet passed on standard input.

Dart API

* `AsyncImporter.canonicalize()` and `Importer.canonicalize()` must now return
absolute URLs. Relative URLs are still supported, but are deprecated and will
be removed in a future release.

* Canonicalize escaped digits at the beginning of identifiers as hex escapes.

* Properly parse property declarations that are both *in* content blocks and
written *after* content blocks.

Command-Line Interface

* Print more readable paths in `--watch` mode.

BREAKING CHANGE

In accordance with our [compatibility policy][], breaking changes made for CSS
compatibility reasons are released as minor version revision after a three-month
deprecation period.

[compatibility policy]: README.mdcompatibility-policy

* Tokens such as `abcd` that are now interpreted as hex colors with alpha
channels, rather than unquoted ID strings.

Node JS

* Tweak JS compilation options to substantially improve performance.

* Properly generate source maps for stylesheets that emit `charset`
declarations.

Command-Line Interface

* Don't error out when passing `--embed-source-maps` along with
`--embed-sources` for stylesheets that contain non-ASCII characters.

* Properly parse `:nth-child()` and `:nth-last-child()` selectors with
whitespace around the argument.

* Don't emit extra whitespace in the arguments for `:nth-child()` and
`:nth-last-child()` selectors.

* Fix support for CSS hacks in plain CSS mode.