read_bytes() - reads a contiguous series of bytes from a file into a string
string read_bytes( string path, int start, int length );
This function reads 'length' bytes beginning at byte # 'start' in the file named 'path'. The bytes are returned as a string. Note that (start + length) must not be past the end of the file or else read_bytes will fail. If the second and third arguments are omitted, the entire file is returned.