silence some policy warnings

CMakeLists.txt

@@ -6,10 +6,14 @@
 # MARK_AS_ADVANCED (BUILD_TESTING CMAKE_BUILD_TYPE=Debug)
 #windows flags: -DDESIRED_QT_VERSION=5 -DCMAKE_PREFIX_PATH=D:\Qt32bit\Qt5.4.1\5.4\msvc2013 -DCMAKE_PREFIX_PATH=VTK.0.0\VTK-7.0.0\build -G "Visual Studio 12 2013"
 #--------------------------------------------------------------------------
-cmake_minimum_required(VERSION 2.8)
+cmake_minimum_required(VERSION 3.1)
 project( jpsvis )
+IF (POLICY CMP0025)
 cmake_policy(SET CMP0025 NEW) #fixes error No known features for CXX compiler (on mac)
-
+ENDIF (POLICY CMP0025)
+IF (POLICY CMP0054)
+cmake_policy(SET CMP0054 NEW)
+ENDIF (POLICY CMP0054)
 MESSAGE( STATUS "System ........................................ ${CMAKE_SYSTEM_NAME} (${CMAKE_SYSTEM_VERSION}, ${CMAKE_SYSTEM_PROCESSOR})" )
 
 list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}")