Create an "empty" CMakeLists.txt to fix the testsuite

Three/demo/Three/CMakeLists.txt

@@ -0,0 +1,27 @@
+# Created by the script cgal_create_cmake_script
+# This is the CMake script for compiling a CGAL application.
+
+
+project( Three_test )
+
+cmake_minimum_required(VERSION 2.8.10)
+
+set(CMAKE_CXX_STANDARD 14)
+
+find_package(CGAL QUIET COMPONENTS Core )
+
+if ( CGAL_FOUND )
+
+  include( ${CGAL_USE_FILE} )
+
+  include( CGAL_CreateSingleSourceCGALProgram )
+
+  include_directories (BEFORE "../../include")
+
+
+else()
+  
+    message(STATUS "This program requires the CGAL library, and will not be compiled.")
+  
+endif()
+