add option to omit panic handlers during development

[mpldr]

While panic recovery handlers are useful in production to make sure the program does not crash, even if a user finds an issue that causes a crash condition. During development, it can sometimes be more useful to properly crash, potentially generating a coredump to enable further debugging.

To allow your program to crash on a panic, add this to your config file:

omit_panic_handler: true

Describe your PR and link to any relevant issues.

I have:

• Added tests covering the bug / feature (see testing)
  • honestly, not sure on how to test a new config field. I have tried it out and verified that it works, though.
• Updated any relevant documentation (see docs)

[coveralls]

coverage: 74.762% (-0.03%) from 74.793%
when pulling 2aedcda on mpldr-pulls:make-go-boom
into 1a7c609 on 99designs:master.

[StevenACoffman]

Thanks!