Remove Windows CE support

Windows CE doesn't seem to be supported by Microsoft any longer. Last CE
release was in early 2013 and the PocketPC and Smartphone targets supported by
wxWidgets are long gone.

The build files where already removed in an earlier cleanup this commit
removes all files, every #ifdef and all documentation regarding the Windows CE
support.

Closes https://github.com/wxWidgets/wxWidgets/pull/81

samples/menu/menu.cpp

@@ -680,9 +680,6 @@ MyFrame::MyFrame()
                  wxT("menubar itself.\n\n")
                  wxT("Right click the band below to test popup menus.\n"));
 #endif
-#ifdef __POCKETPC__
-    EnableContextMenu();
-#endif
 }
 
 MyFrame::~MyFrame()
@@ -1330,9 +1327,6 @@ MyDialog::MyDialog(wxWindow* parent)
     m_textctrl->AppendText(wxT("Dialogs do not have menus, but popup menus should function the same\n\n")
                  wxT("Right click this text ctrl to test popup menus.\n"));
 #endif
-#ifdef __POCKETPC__
-    EnableContextMenu();
-#endif
 }
 
 #if USE_LOG_WINDOW