Merge branch 'duneproject-cmake-3.1' into 'master'

Require CMake 3.1 when creating new modules with duneproject.

See merge request !429

(cherry picked from commit d5ab5050)

07cfb47d Require CMake 3.1 when creating new modules with duneproject.

bin/duneproject

@@ -384,7 +384,9 @@ R_DELIM
 ################## CMakeLists.txt ##################
 echo "- $PROJECT/CMakeLists.txt"
 cat> "$PROJECT/CMakeLists.txt" << M_DELIM
-cmake_minimum_required(VERSION 2.8.12)
+# We require version CMake version 3.1 to prevent issues
+# with dune_enable_all_packages and older CMake versions.
+cmake_minimum_required(VERSION 3.1)
 project($PROJECT CXX)
 
 if(NOT (dune-common_DIR OR dune-common_ROOT OR