Bug in how to defined the mid-points

j_mid = (numpy.shape(T)[0]+1)/2
i_mid = (numpy.shape(T)[1]+1)/2 are not the mids point
for example if T is (5,5) then (j_mid, i_mid) = 3,3 and
should be (2,2). So the +1 shouldn't be there.
Merge pull request #107 from ncclementi/temp2

Bug in how to defined the mid-points