
I would like you to implement a module named TopModule with the following
interface. All input and output ports are one bit unless otherwise
specified.

 - input  in (4 bits)
 - output out_and
 - output out_or
 - output out_xor

The module should implement a combinational circuit with four inputs,
in[3:0]. There are 3 outputs:

  (1) out_and : output of a 4-input AND gate
  (2) out_or  : output of a 4-input OR  gate
  (3) out_xor : output of a 4-input XOR gate

