Fix overload tag in YARD docs
Fix marshaling of mixin def node with variable arguments
Fix rubocop line-length errors.
Merge branch 'fix-yard-overloads' into stable

Closes #z1169
Style cleanups.
Add a few more missing option sets.
Merge branch 'fix-splat-marshaling' into stable

Closes #1171
Add a changelog entry for the marshaling fix.
Bump VERSION to 3.3.3.
Handle race condition in the filesystem cache.
Build the 3.2 stable branch with Travis when there are changes.
Bump VERSION to 3.2.16.
Update changelog for race condition fix.
Merge branch 'stable_3_2' into stable

Conflicts:
	VERSION
	doc-src/SASS_CHANGELOG.md
Don't freeze nil.

In Ruby, the nil singleton object is not frozen. Freezing it breaks
some other gems.

~$ irb
2.1.1 :001 > nil.frozen?
 => false

Conveniently, the `unless` syntax leaves `@value` as good ol' nil,
so there's no need for a ternary.
Ensure atomic writes are fully flushed to disk.
Bump VERSION to 3.2.17.
Remove whitespace
Fix some typos
Merge branch 'stable_3_2' without the changes.

Recent changes to stable_3_2 are not needed on stable, this merge
ensures we won't try to merge them in at a later point.