Update cmake required version to 3.5

This simplifies policy and version set up.

CMakeLists.txt

@@ -1,21 +1,10 @@
-cmake_minimum_required(VERSION 2.8.12)
-#To avoid OpenMP warning: https://gitlab.kitware.com/cmake/cmake/issues/17292
-if(POLICY CMP0054)
-      cmake_policy(SET CMP0054 NEW)
-endif()
+cmake_minimum_required(VERSION 3.5)
 
 project(proxTV
         DESCRIPTION "Toolbox for fast Total Variation proximity operators"
-        LANGUAGES C CXX
+        VERSION 3.2.1
         )
 
-# Set VERSION
-# Since cmake v3.0 we can just give an option to project(proxTV VERSION 3.2.1 LANGUAGES C CXX)
-set(proxTV_VERSION_MAJOR 3)
-set(proxTV_VERSION_MINOR 2)
-set(proxTV_VERSION_PATCH 1)
-# set(proxTV_VERSION_TWEAK 0)
-set(proxTV_VERSION "${proxTV_VERSION_MAJOR}.${proxTV_VERSION_MINOR}.${proxTV_VERSION_PATCH}")
 message(STATUS "proxTV version: ${proxTV_VERSION}")
 
 # External Dependencies: {{{