Remove unnecessary copy ctors/copy assignment operators

C++11 deprecates having one without the other.
Eliminates many, many GCC -Wdeprecated-copy warnings.

include/wx/unichar.h

@@ -144,7 +144,6 @@ public:
     bool operator&&(bool v) const { return (bool)*this && v; }
 
     // Assignment operators:
-    wxUniChar& operator=(const wxUniChar& c) { if (&c != this) m_value = c.m_value; return *this; }
     wxUniChar& operator=(const wxUniCharRef& c);
     wxUniChar& operator=(char c) { m_value = From8bit(c); return *this; }
     wxUniChar& operator=(unsigned char c) { m_value = From8bit((char)c); return *this; }