Add typed array types to js2-node-externs

node.js has supported typed arrays since 0.6:

https://github.com/joyent/node/wiki/API-changes-between-v0.4-and-v0.6
https://github.com/joyent/node/issues/1322
https://github.com/joyent/node/commit/97b0000

I could've/should've moved these into `js2-typed-array-externs` (with corresponding feature-toggle `js2-include-typed-array-externs`). I'd be happy to do so if that seems like the superior option, but js2-mode is quite the beast and I didn't want to change more than absolutely necessary.