maint: Use space after function name/before parenthesis in libgui. * Backend.cc, ButtonControl.cc, ButtonGroup.cc, Canvas.cc, Container.cc, EditControl.cc, GLCanvas.cc, ListBoxControl.cc, ListBoxControl.h, PopupMenuControl.cc, QtHandlesUtils.cc, TextControl.cc, TextEdit.h, annotation-dialog.cc, annotation-dialog.h, gl-select.cc, dialog.cc, files-dock-widget.cc, find-files-dialog.cc, history-dock-widget.cc, file-editor-tab.cc, file-editor.cc, file-editor.h, find-dialog.cc, marker.cc, octave-qscintilla.cc, octave-qscintilla.h, main-window.cc, octave-dock-widget.cc, octave-dock-widget.h, octave-gui.cc, parser.cc, parser.h, webinfo.cc, settings-dialog.cc, shortcut-manager.cc, welcome-wizard.cc, workspace-view.cc: Use space after function name and before parenthesis.

--- a/libgui/graphics/annotation-dialog.h	Wed Jan 18 17:48:32 2017 -0500
+++ b/libgui/graphics/annotation-dialog.h	Wed Jan 18 17:36:36 2017 -0800
@@ -41,7 +41,7 @@
   explicit annotation_dialog (QWidget * parent, const octave_value_list &pr);
   ~annotation_dialog ();
 
-  octave_value_list get_properties() const;
+  octave_value_list get_properties () const;
 
 private slots:
   // slots for dialog's buttons
@@ -50,7 +50,7 @@
   void prompt_for_color ();
 
 private:
-  void init();
+  void init ();
 
   void get_gui_props ();
   void set_gui_props ();