Fix User Chart Axis Hover bug

.. turns out the jsonunprotect function wasn't stripping the trailing
   spaces that jsonprotect was adding. This caused axis labels to have
   spaces at the end that the qt charts code stripped-- so when we went
   looking for axis label texts they didn't match.

.. this commit causes jsonunprotect to strip trailing spaces. This
   should not result in any regression as use of jsonunprotect is
   limited to HomeWindow properties.

src/Core/Utils.cpp

@@ -217,6 +217,9 @@ QString jsonunprotect(const QString &string)
     s.replace("\\f", "\f");  // formfeed
     s.replace("\\/", "/");   // solidus
     s.replace("\\\\", "\\"); // backslash
+
+    // those trailing spaces.
+    while (s.endsWith(" ")) s = s.mid(0,s.length()-1);
     return s;
 }