#196 co-expression source is not correct

[Art Eschenlauer]

End of output from co.icn (attached, provided by Jafar) is:

S=>B
B source is NOT correct: co-expression_4(0) ~== co-expression_2(0)

B=>A
A source is NOT correct: co-expression_1(1) ~== co-expression_3(0)

A=>S
S source is NOT correct: co-expression_3(0) ~== co-expression_4(0)
S is done

A=>main
&main source is NOT correct: co-expression_1(1) ~== co-expression_4(0)

main=>B
B source is NOT correct: co-expression_4(0) ~== co-expression_1(1)
B is done

[Charles Evans]

Added test co to tests/coexpr, [r5634]