Additional Chaos Monkey email properties

**Add properties for Chaos Monkey email notifications to:**
- Add a prefix and/or suffix to subject text
- Add a prefix and/or suffix to body text
- Make the subject and body the same (to include Instance and Group information)
- Combinations of the above

**Background:**
Various CMs are running on different accounts sending to one email address, there is a requirement to identify the sending Monkey/Account. Prefix/Suffix came from this and seems like some generally useful flexibility. 

Subject matching body seemed like a simple way to include the extra information in the subject rather than the standard generic text.

**Note:**
Included a commit that isn't directly related but adds to the default configuration file properties for global email notification options as mentioned in https://github.com/Netflix/SimianArmy/wiki/Chaos-Settings