Add support in _.isEmpty and _.size for jQuery/MooTools DOM query collections.

Former-commit-id: dc834256d09d7a3f2797ba65690961aad00717bf

build/pre-compile.js

@@ -43,6 +43,7 @@
     'ArrayProto',
     'bind',
     'callee',
+    'className',
     'compareAscending',
     'destValue',
     'forIn',
@@ -57,6 +58,7 @@
     'isPlainObject',
     'methodName',
     'noaccum',
+    'objectClass',
     'objectTypes',
     'pass',
     'properties',