Log Message:
Changes 3.3.4:
Fixes:
* Inconsistent error message produced when nesting functions and mixins
* Ensure custom importers are executed for all @imports
* Ensure custom importers are executed in the correct order
* Possible segfault when generating sourcemaps
* Memory leak
* Unused variable warning
* Segfaulting when @extending an undefined selector
* Incorrectly erring when @extending inside a mixin
* Handle signed char when considering @charset
* New link to sassc-ruby in documentation
* Incorrectly quoting interpolated strings join with +
* Incorrectly erring when using & and interpolation together
* Incorrectly duplicating nested pseudo selectors
* Unused function breaking breaking unity builds
* Segfaulting when url() is empty
* Should error when & is used without a parent selector