add sysinternals suite

It just downloads and creates the shims now.

It might be nice to accept all the EULAs, as described [here](http://forum.sysinternals.com/topic9038&KW=eulaaccepted.html), in a post_install, but I am not sure if that would violate the EULA or something like that. Leaving that out for now.

I think this what's being asked for in lukesampson/scoop#3?