Regexes cannot be passed to FileList.exclude.

Example of the problem:

```
> (new JAKE.FileList("*")).exclude(/(^|[\/\\])\.git([\/\\]|$)/)
TypeError: Result of expression 'aFunction.apply' [undefined] is not a function.
```

paulbaumgart@6f3ac72655 fixes this bug, so instead you get:

```
> (new JAKE.FileList("*")).exclude(/(^|[\/\\])\.git([\/\\]|$)/)
bin lib LICENSE package.json README.md
```
