update windows binary

This tests cleanly on Win64 now.

You can generate these automatically on AppVeyor from a fork of the ECOS repository with this yml: https://github.com/tkelman/ecos/blob/0e53f6e53f38d44b9d8299d6a8faaec7f3dcdf69/appveyor.yml however that's not ideal because it results in a new SHA that doesn't exist upstream.

You probably want to turn on AppVeyor for ECOS.jl for testing purposes, and make sure to either create a new Windows binary and/or copy the existing version number for the sake of the Windows binary next time a Linux version bump is desired.