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

src/common/sizer.cpp

@@ -2709,18 +2709,11 @@ bool wxStaticBoxSizer::Detach( wxWindow *window )
 wxStdDialogButtonSizer::wxStdDialogButtonSizer()
     : wxBoxSizer(wxHORIZONTAL)
 {
-    // Vertical buttons with lots of space on either side
-    // looks rubbish on WinCE, so let's not do this for now.
-    // If we are going to use vertical buttons, we should
-    // put the sizer to the right of other controls in the dialog,
-    // and that's beyond the scope of this sizer.
-#ifndef __WXWINCE__
     bool is_pda = (wxSystemSettings::GetScreenType() <= wxSYS_SCREEN_PDA);
     // If we have a PDA screen, put yes/no button over
     // all other buttons, otherwise on the left side.
     if (is_pda)
         m_orient = wxVERTICAL;
-#endif
 
     m_buttonAffirmative = NULL;
     m_buttonApply = NULL;