Fix remaining toAscii/fromAscii

Qt5 does not have toAscii or fromAscii.  Use toLatin1 and fromLatin1
respectively.  Both replacement functions exist in Qt4.8.

src/Tools/ImageTools/ImageConv/main.cpp

@@ -136,7 +136,7 @@ int main( int argc, char **argv )
     }
     catch(const CICException& e)
     {
-        cerr << (const char*)e.what().toAscii() << endl;
+        cerr << (const char*)e.what().toLatin1() << endl;
         CImageConvApp::Error();
     }
     catch(...)