Overrode sendTerminationNotification() method in
CloudFormationChaosMonkey class to enable email notifications when
no-suffix group names are used.

Modified BasicChaosMonkey and BasicChaosEmailNotifier classes to enable
global email notifications. eg.
simianarmy.chaos.notification.global.receiverEmail = test@email.com
is used to enable global email notifications. Added corresponding unit
test.

Refactored TestChaosMonkeyContext to remove duplicate code
- 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()]
- Using StringUtils.isBlank() to check for empty email address (based on
suggestion by michaelnflx)
- Logging at INFO level when both global and group notifications are
sent out to differential between them
Merge pull request #68 from nicktgr15/master

Email notification changes