Support fs.readFile options / Strip byte order mark

* Added an ability to accept [`fs.readFile`](http://nodejs.org/api/fs.html#fs_fs_readfile_filename_options_callback) options
* Strip BOM since [`fs.readFile` doesn't strip it](https://github.com/joyent/node/issues/1918)
* Updated `.npmignore` to exclude `.travis.yml`