Improve error handling & fix null pointer exceptions for login and graph calls
Improve error logging and support handling of canceled user login request
Improve cancel dialog handling by passing the error code additionally  and fix possible error in user facing error messages
Only handle dialog canceled exception to support token recovery behavior by FB SDK
Refactor error message handling
Merge branch 'develop' of https://github.com/Wizcorp/phonegap-facebook-plugin into better-error-handling

Conflicts:
	platforms/android/src/org/apache/cordova/facebook/ConnectPlugin.java
Also handle unexpected authentication terminations where no exception is present (e.g. age restriction)
Add missing import (manual back-merging fail)
Remove space
Merge pull request #716 from platogo/better-error-handling

Better error handling