first phase of transition to unified Unicode build:

1. changed c_str() to return wxCStrData (implicitly convertible to wxChar*)
2. added template type-safe wrappers for vararg functions
3. added wxUniChar class representing single Unicode character
4. changed wxString::operator[] and wxString::iterator to return wxUniChar


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@44865 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

tests/test.bkl

@@ -46,7 +46,9 @@
             strings/strings.cpp
             strings/stdstrings.cpp
             strings/tokenizer.cpp
+            strings/unichar.cpp
             strings/unicode.cpp
+            strings/vararg.cpp
             strings/crt.cpp
             strings/vsnprintf.cpp
             streams/bstream.cpp