Performance improvements and backpressure controls.

Simply and speed up command argument processing logic.
Commands now return the true/false value from the underlying socket write(s).
Implement command_queue high water and low water for more better control of queueing.

lib/to_array.js

@@ -1,4 +1,3 @@
-// the "new Array(len)" syntax is legal and optimized by V8, but JSHint is utterly confused by it.
 function to_array(args) {
     var len = args.length,
         arr = new Array(len), i;
@@ -8,6 +7,6 @@ function to_array(args) {
     }
 
     return arr;
-};
+}
 
 module.exports = to_array;