log.wordlist now accepts an array of colors in options

Updated the wordlist method to accept an array of colors to color each item individually.

Example:

```
grunt.log.wordlist(['first', 'second ', 'third'], {
  color: ['green', 'blue', 'red']
});
```

There weren't any tests written for wordlist so I haven't included any with this update. I have tested locally not passing a value, passing a single value, passing an array of values, passing a falsy value. Each of these behaved as expected.

The only cavat currently is the number of colors must match the number of words or the word will be omitted. 

Example:

```
grunt.log.wordlist(['first', 'second ', 'third'], {
  color: ['green', 'blue']
});
```

Would return: ```first, second,```

I didn't put checks in for this because I was trying to keep the change small.