Add missing overloads in SaneOutputStream.

These missing overloads were causing JFreeSane to utilize the TCP stream in a
rather inefficient manner (e.g. write 4 bytes yields a one-byte packet and then
a three-byte packet rather than one four-byte packet).

This wouldn't have caused any noticable latency unless the user has a very slow
link, but it's tidier now.
Add missing overloads in SaneInputStream.

The previous implementation delegated these methods to the zero-parameter read
version, likely much less efficient than the read(byte[]) and read(byte[],
offset, len) methods.