wx3.0: lots of cast...

Various string as still wrong but at least it can be compiled now.

I think the remaining issue are w_char with %s format (at least on linux)
wx3.0: various interface update
wx3.0: various buggy code (wx assertion)
wx3.0: disable an useless symbol on linux

Not used and print an error message for each plugins.
wx3.0: fix various string printing on linux (but windows could be broken now)

Unicode must use %ls format on linux (let's hope it work on windows too)