- added a property to signal that global email notification is enabled
[globalNotificationEnabled.properties]
- separated group email notification logic from global email
notification logic [BasicChaosMonkey.java, ChaosEmailNotifier.java,
BasicChaosEmailNotifier.java]
- added a counter in test context to track global email notifications
[TestChaosMonkeyContext.java]
- added an assert to verify count of global email notifications
[TestBasicChaosMonkey.java -> testGlobalNotificationEnabled()]