Install to RUST_PATH instead of /usr/local/lib

This means we don't need to worry about the glfw-rs lib conflicting with the local installation of glfw, so we can use "github.com/bjz/glfw-rs#glfw:0.1" for the crate_id again.
Fix LogErrorHandler
Merge pull request #111 from bjz/log

Install to RUST_PATH and fix build