Use wxTextProofOptions itself to enable or disable the checks

Remove a separate "bool enable" argument of EnableProofCheck() and use
wxTextProofOptions::IsSpellCheckingEnabled() to decide whether the
checks should be enabled or disabled.

Also remove wxTextProofOptions ctor and provide named static factory
functions for creating the objects of this class with clearly defined
meaning.

src/msw/textctrl.cpp

@@ -834,7 +834,7 @@ WXDWORD wxTextCtrl::MSWGetStyle(long style, WXDWORD *exstyle) const
 
 #if wxUSE_RICHEDIT && wxUSE_SPELLCHECK
 
-bool wxTextCtrl::EnableProofCheck(bool enable, const wxTextProofOptions& WXUNUSED(options))
+bool wxTextCtrl::EnableProofCheck(const wxTextProofOptions& options)
 {
     wxCHECK_MSG((m_windowStyle & wxTE_RICH2), false,
             "Unable to enable proof checking on a control "
@@ -846,7 +846,7 @@ bool wxTextCtrl::EnableProofCheck(bool enable, const wxTextProofOptions& WXUNUSE
 
     LRESULT langOptions = ::SendMessage(GetHwnd(), EM_GETLANGOPTIONS, 0, 0);
 
-    if ( enable )
+    if ( options.IsSpellCheckingEnabled() )
         langOptions |= IMF_SPELLCHECKING;
     else
         langOptions &= ~IMF_SPELLCHECKING;