Tiny speedup by removing command.toLowerCase()

This is not necessary as the command itself is only used from inside the code and as they are (now) all lower case it is safe to remove the toLowerCase

test/commands/eval.spec.js

@@ -35,7 +35,7 @@ describe("The 'eval' method", function () {
             });
 
             it('returns a string', function (done) {
-                client.eval("return 'hello world'", 0, helper.isString('hello world', done));
+                client.EVAL("return 'hello world'", 0, helper.isString('hello world', done));
             });
 
             it('converts boolean true to integer 1', function (done) {