Fixing sass-spec 010_test_multiple_extends_with_multiple_extenders_and_single_target. We were not properly comparing selectors when putting them into our collection. We relied on Complex_Selector operator less than, but it was simply doing a string comparision. This doesn't treat .a.b the same as .b.a, but we need that behavior since that's closer to what ruby sass does. The fix was to implement operator== for Complex_Selector, Compound_Selector, and Simple_Selector. We compare Complex_Selector and Compound_Selector similarly to how ruby sass does. We still use string comparision for Simple_Selector.
Merge branch 'feature/extend-support' of github.com:DealerDotCom/libsass into feature/extend-support