maint: Use convention 'int& x' for naming references. * ButtonGroup.cc, Canvas.cc, Canvas.h, annotation-dialog.cc, annotation-dialog.h, dialog.h, documentation-dock-widget.cc, files-dock-widget.cc, files-dock-widget.h, find-files-dialog.cc, find-files-dialog.h, find-files-model.cc, find-files-model.h, history-dock-widget.cc, history-dock-widget.h, file-editor-tab.cc, file-editor-tab.h, file-editor.cc, file-editor.h, main-window.cc, main-window.h, octave-qt-link.h, parser.cc, parser.h, webinfo.cc, webinfo.h, settings-dialog.cc, bsxfun.cc, call-stack.cc, call-stack.h, fft.cc, fft2.cc, fftn.cc, gl-render.cc, graphics.cc, graphics.in.h, input.cc, load-save.cc, ls-hdf5.cc, ls-hdf5.h, octave-link.h, pr-output.cc, regexp.cc, sparse-xdiv.cc, sparse-xdiv.h, symtab.cc, xdiv.cc, xdiv.h, zfstream.h, __eigs__.cc, __ode15__.cc, ov-base.h, ov-builtin.cc, ov-cx-sparse.h, ov-fcn-handle.cc, ov-fcn-handle.h, ov.cc, ov.h, jit-ir.h, jit-typeinfo.cc, jit-typeinfo.h, pt-jit.cc, pt-jit.h, CMatrix.cc, CMatrix.h, CSparse.cc, CSparse.h, MatrixType.cc, MatrixType.h, dDiagMatrix.cc, dMatrix.cc, dMatrix.h, dSparse.cc, dSparse.h, fCMatrix.cc, fCMatrix.h, fDiagMatrix.cc, fMatrix.cc, fMatrix.h, eigs-base.cc, oct-fftw.cc, oct-rand.h, sparse-dmsolve.cc, kpse.cc, lo-regexp.h: Use convention 'int& x' for naming references.

--- a/libinterp/corefcn/graphics.in.h	Mon Apr 24 14:38:34 2017 -0700
+++ b/libinterp/corefcn/graphics.in.h	Mon Apr 24 17:20:37 2017 -0700
@@ -2784,7 +2784,7 @@
     get_properties ().override_defaults (obj);
   }
 
-  void build_user_defaults_map (property_list::pval_map_type &def,
+  void build_user_defaults_map (property_list::pval_map_type& def,
                                 const std::string go_name) const;
 
   virtual void set_from_list (property_list& plist)
@@ -3049,7 +3049,7 @@
     rep->override_defaults (*rep);
   }
 
-  void build_user_defaults_map (property_list::pval_map_type &def,
+  void build_user_defaults_map (property_list::pval_map_type& def,
                                 const std::string go_name) const
   {
     rep->build_user_defaults_map (def, go_name);
@@ -5135,7 +5135,7 @@
 
     // Matlab allows incoherent data to be stored into patch properties.
     // The patch should then be ignored by the renderer.
-    bool has_bad_data (std::string &msg) const
+    bool has_bad_data (std::string& msg) const
     {
       msg = bad_data_msg;
       return ! msg.empty ();