Adheres to the Rule of Silence (+ unique exitcode)

The Rule of Silence (http://www.linfo.org/rule_of_silence.html) exists for a reason.

This commit/PR addresses that.

Also, sets a unique exit code for each exit.
Merge pull request #9 from adamamyl/master

[#8] Adheres to the Rule of Silence (+ unique exitcode)

Merged, thanks!