Dart-sass

Command-Line Interface

* Add a `--poll` flag to make `--watch` mode repeatedly check the filesystem for
updates rather than relying on native filesystem notifications.

* Add a `--stop-on-error` flag to stop compiling additional files once an error
is encountered.

* No user-visible changes.

* Add a deprecation warning for `-moz-document`, except for cases where only an
empty `url-prefix()` is used. Support is [being removed from Firefox][] and
will eventually be removed from Sass as well.

[being removed from Firefox]: https://www.fxsitecompat.com/en-CA/docs/2018/moz-document-support-has-been-dropped-except-for-empty-url-prefix/

* Fix a bug where `-moz-document` functions with string arguments weren't being
parsed.

Command-Line Interface

* Don't crash when a syntax error is added to a watched file.

* Fix crashes in released binaries.

* Emit deprecation warnings for tokens such as `abcd` that are ambiguous
between ID strings and hex colors with alpha channels. These will be
interpreted as colors in a release on or after 19 September 2018.

* Parse unambiguous hex colors with alpha channels as colors.

* Fix a bug where relative imports from files on the load path could look in the
incorrect location.

Command-Line Interface

* Fix a bug where the source map comment in the generated CSS could refer to the
source map file using an incorrect URL.