Add flow, example implementation and types

.flowconfig

@@ -0,0 +1,12 @@
+[ignore]
+<PROJECT_ROOT>/node_modules/.*
+
+[libs]
+
+[options]
+esproposal.decorators=ignore
+esproposal.class_static_fields=enable
+esproposal.class_instance_fields=enable
+unsafe.enable_getters_and_setters=true
+module.name_mapper='^\(.*\)\.s?css$' -> 'empty/object'
+module.file_ext=.scss