CPack post (un)install

add post (un)install scripts to musrfit cpack. Currently for rpm only. Furthermore a minimal required root version is added. Will need to see if this is sufficient or if more detailed work needs to be added.

cmake/post_uninstall.sh

@@ -0,0 +1,13 @@
+#!/bin/bash
+
+echo ">> musrfit post uninstall script started ..."
+
+# test if nemu-x86_64.conf does not exist
+if [ -f "/etc/ld.so.conf.d/nemu-x86_64.conf" ]
+then
+  rm -f /etc/ld.so.conf.d/nemu-x86_64.conf  
+fi
+/sbin/ldconfig
+
+echo ">> musrfit post uninstall script done."
+