All file I/O should now go via wchar on Windows
Needs to be tested, though
Compilation fixed for: chown, lchown, symlink, lstat, mkdir
Compilation fixed for: execve, execv, fstat
libcore_io_Posix now compiles with Unicode file I/O for Windows
mingw-extensions now compile
libavian.a now compiles and links, and demo applications using it link okay