Download and return an file (object) or a specified byte_range from it.
			Version keyword is API-specific, see "etag" file info key:
				http://developers.box.com/docs/#files-file-object-2
			See HTTP Range header (rfc2616) for possible byte_range formats,
				some examples: "0-499" - byte offsets 0-499 (inclusive), "-500" - final 500 bytes.

def get(self, file_id, byte_range=None, version=None):
		'''Download and return an file (object) or a specified byte_range from it.
			Version keyword is API-specific, see "etag" file info key:
				http://developers.box.com/docs/#files-file-object-2
			See HTTP Range header (rfc2616) for possible byte_range formats,
				some examples: "0-499" - byte offsets 0-499 (inclusive), "-500" - final 500 bytes.'''
		kwz = dict()
		if byte_range: kwz['headers'] = dict(Range='bytes={}'.format(byte_range))
		return self(join('files', bytes(file_id), 'content'), dict(version=version), raw=True, **kwz)