Test of production code for gamma function

Test values from -75 to 75

Maximum relative error
   arguments >= 1:          2.4e-14
   arguments <  1:          4.2e-14

Now do logs

Maximum relative error
   arguments >= 1:          2.2e-15
   arguments <  1:          4.0e-15
error at 1 (should be 0):   0.0e+00
error at 2 (should be 0):   0.0e+00

Number of sign errors (should be 0) = 0

Test with integer z in range 100 to 10000

Maximum relative error =    0.0e+00

Test for z near 1 or 2
Maximum relative error =    6.8e-14

