[SPARK-4017] show progress bar in console and title

The progress bar will look like this:

![1___spark_job__85_250_finished__4_are_running___java_](https://cloud.githubusercontent.com/assets/40902/4854813/a02f44ac-6099-11e4-9060-7c73a73151d6.png)

In the right corner, the numbers are: finished tasks, running tasks, total tasks, and used time since beginning.

After the stage has finished, it will show a line of summary for it.

Also, the status will be showed in the title of console.

The progress bar is only showed if logging level is WARN or higher (but progress in title is still showed), it can be turned off by spark.driver.showConsoleProgress.


Maybe we could explicitly say `min=*/median=*/avg=*/max=*` to make this clearer to useres?