Fixing Windows build errors
Fixing Windows build errors

As of nan@1.7.x, NanThrowError does not return anything: https://github.com/rvagg/nan#nanthrowerrormessage-nanthrowtypeerrormessage-nanthrowrangeerrormessage-nanthrowerrorlocalvalue-nanthrowerrorlocalvalue-int

Closes chjj/pty.js#111.

JamesMGreene/node-partty,JamesMGreene/node-partty,JamesMGreene/node-partty