Allow compiling on VS with (/Zc:wchar_t-) set.

git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@4966 dfc29bdd-3216-0410-991c-e03cc46cb475
bugfix: CUserPointerAttribute::setString had used wrong scanf string parameters (and as far as I can see never worked).

git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@4967 dfc29bdd-3216-0410-991c-e03cc46cb475