Add setImmediate, setTimeout and other Timer functions

[LostAbaddon]

Change log:

1. Change the console output format;
2. Set the behaviour of nextTick just like what the node.js do;
3. Add setImmediate function and it functions just like what in node.js;
4. Add setTimeout, clearTimeout, setInterval, clearInterval functions and they function just like what in node.js.

Problem remains:
The new functions will be called each while loop, so the CPU usage will be high.