Improve default UncaughtException handler
Merge pull request #4 from danjenkins/master

Added in callback support for notify and nofifyWithClass
Merge branch 'master' of github.com:bugsnag/bugsnag-node
Bump version and add callback on notify
Pull package version out on require
Always honour notifyReleaseStages
Merge pull request #6 from bugsnag/notifyReleaseStages

Always honour notifyReleaseStages
Bump version and update README
Adding in support for callbacks even when there is no request due to release stage incompatability
move checks on notify stage/key so we check earlier on and give back a callback result