0.7 wip

Pulled in @brett19's changes and added him as a collab.

Finally removed that deprecated `NanCallback#Run` method!

Also, I was playing with https://github.com/yahoo/monitr/blob/master/src/monitor.cc and they're using v8-debug as well which also comes along with some painful API changes. Was thinking about perhaps having a nan-debug.h to track those changes. Not that this'll hold up an 0.7 release though.

Any more changes anyone want to get in before I release this as 0.7.0?