remove GPL3 license terms from src/USER-PACE/pair_pace.*

delete lib/pace/CMakeLists.txt

src/USER-PACE/pair_pace.cpp

@@ -7,21 +7,7 @@ Copyright 2021 Yury Lysogorskiy^1, Cas van der Oord^2, Anton Bochkarev^1,
 ^2: University of Cambridge, Cambridge, United Kingdom
 ^3: Sandia National Laboratories, Albuquerque, New Mexico, USA
 ^4: University of British Columbia, Vancouver, BC, Canada
-
-
-    This FILENAME 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/>.
- */
+*/
 
 
 //