Use .tools/ folder of package as destination for optipng binaries, fix optipng’s Ketarin job

I’m not really a fan of putting things directly into the root of the system drive (like this package previously did with `C:\OptiPNG`).

Why not put it into the `./tools` folder of the package? Then it is also not necessary to add stuff to the PATH variable, because SihmGen already handles it.

In addition your Ketarin job for optipng was broken (SourceForge again).

As soon as you merge this, don’t forget to release the fixed version of this package (e.g. v0.7.5.201408…).