TinyXML2 with full unicode (wchar_t/wchar) support

[swdukk]

in case anyone interested (and searching WWW for it), i ported single byte (char) version of new tinyxml2 fast and simple XML library to wchar_t string type. 
tinyxml2.cpp nbsp; and  tinyxml2.h nbsp;
tested on original testxml.cpp samples

i hope this will save someone coding time...

changes to original TinyXML2:
+all char goes wchar_t
+read / write file methods works only with unicode files
+added function IterateChildren() from tinyxml first version to seamless lib integration with old projects
+added overloaded function SetAttribute() with __int64 datatype.