add GPL to sphear_af_power.m

sphear_af_power.m

@@ -15,7 +15,20 @@
 %% input parameters
 %%
 %% Copyright Fernando Lopez-Lezcano 2016
-%% 
+%% nando@ccrma.stanford.edu
+%%
+%%  This program is free software: you can redistribute it and/or modify
+%%  it under the terms of the GNU General Public License as published by
+%%  the Free Software Foundation, either version 3 of the License, or
+%%  (at your option) any later version.
+%%
+%%  This program is distributed in the hope that it will be useful,
+%%  but WITHOUT ANY WARRANTY; without even the implied warranty of
+%%  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+%%  GNU General Public License for more details.
+%%
+%%  You should have received a copy of the GNU General Public License
+%%  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 function [R] = sphear_af_power(measurements, fmin, fmax, N, Npre)
   pkg load signal;