Fix 'cast increases required alignment of target type' warnings (some of them...

Fix 'cast increases required alignment of target type' warnings (some of them are fixed by handling different wchar_t sizes through overloading, others - by casting to void* since we know the alignment restrictions are not violated)

git-svn-id: http://pugixml.googlecode.com/svn/trunk@838 99668b35-9821-0410-8761-19e4c4f06640