Adding support for automation tools feature.

Adding "build" command for supporting automation tools like Continuous Integration. It has its own default workspace like in /demo. 

You can provide it (source files, destination files, config file) with the parameters for your own script like this.
```
$ grunt build --src-`source path` --dst=`destination path` --config=`configuration path`
```

By combine `grunt` option `--gruntfile` with this 'build' command. It can make more ways to do with this JSDoc template.

P.S. I also edit README.md file for better understanding and the example usage for 'build' command.