made the Qt finder look for the newer Qt5Core_VERSION variable and set...

made the Qt finder look for the newer Qt5Core_VERSION variable and set Qt5Core_VERSION_STRING to Qt5Core_VERSION if it is found.
This is needed since qt59 does not set the Qt5Core_VERSION_STRING variable properly, which is fine, as this variable is deprecated anyways.

cmake/ACGQt.cmake

@@ -32,6 +32,9 @@ macro (acg_qt5)
     
     find_package (Qt5Core QUIET)
     if(Qt5Core_FOUND)
+        if(Qt5Core_VERSION) # use the new version variable if it is set
+            set(Qt5Core_VERSION_STRING ${Qt5Core_VERSION})
+        endif(Qt5Core_VERSION)
         string(REGEX REPLACE "^([0-9]+)\\.[0-9]+\\.[0-9]+.*" "\\1" QT_VERSION_MAJOR "${Qt5Core_VERSION_STRING}")
         string(REGEX REPLACE "^[0-9]+\\.([0-9])+\\.[0-9]+.*" "\\1" QT_VERSION_MINOR "${Qt5Core_VERSION_STRING}")
         string(REGEX REPLACE "^[0-9]+\\.[0-9]+\\.([0-9]+).*" "\\1" QT_VERSION_PATCH "${Qt5Core_VERSION_STRING}")