Fixed a typo in the documentation.

Mixins can take -arguments- SassScript values as arguments
Merge pull request #1308 from sumul/stable

Fixed a typo in the documentation.
Properly URL-encode URLs in sourcemaps.

Closes #1306
Support "--suffix" for selector-append.

This has a side effect of supporting most "--foo"-style identifiers.

Closes #1310
See #1128
Merge remote-tracking branch 'origin/stable' into stable
Merge branch 'stable'

Conflicts:
	doc-src/SASS_CHANGELOG.md
	lib/sass/importers/base.rb
	lib/sass/util.rb