Copy files if fs.link fails
Copy files if fs.link fails

References #2
- Adds a test and property, `canLink`, to establish whether `fs.link` or `fs.writeFile` should be used
- Semicolons;

ember-cli/broccoli-caching-writer,stefanpenner/broccoli-caching-writer,jasonmit/broccoli-caching-writer,joliss/broccoli-caching-writer,twokul/broccoli-caching-writer,chadhietala/broccoli-caching-writer