critical values for the Schmidt-Phillips statistic
[critical1,critical2]=schmiphi_tab(p,T)
p: order of the polynomial trend
T: # of observations
critical1: (1% - 2.5% - 5% -10%) critical values of the rho test
critical2: (1% - 2.5% - 5% -10%) critical values of the tau test
[c1,c2]=schmiphi_tab(1,100) // Provides Schmidt and Phillips table for a model with a simple trend and 100 observations.