Make access to the dependency cache threadsafe.
Merge branch 'threadsafe_dependency_cache' into stable
Atomically write to the Sass cache.
Merge branch 'atomic_writes' into stable
Add a changelog entry about thread-safety fixes.
Bump VERSION to 3.2.11.
Document Sass::Util#escape_uri.
Merge branch 'stable'

Conflicts:
	VERSION
	doc-src/SASS_CHANGELOG.md
	test/sass/util_test.rb