Gets to file infos in a single box.
		Args:
			box_key		key for the file 
			return		(status code, list of file info dicts)

def get_box_files(self, box_key):
		'''Gets to file infos in a single box.
		Args:
			box_key		key for the file 
			return		(status code, list of file info dicts)
		'''
		uri = '/'.join([self.api_uri,
						self.boxes_suffix,
						box_key,
						self.files_suffix
						])

		return self._req('get', uri)