Change 'prettify' option to 'multiline'

Traditionally "prettify" is used to describe a process that expands code. For example 

http://jsbeautifier.org/ would transform this into what prettify:false does. 

```
this["JST"]["test/fixtures/template.html"] = function(obj) {var __t, __p = '', __e = _.escape;__p += '<head><title>' +((__t = ( obj.title )) == null ? '' : __t) +'</title></head>';return __p};
```
