Merge pull request #9 from mbbx6spp/things-you-should-know-in-bash

Add 'Things You Should Know In Bash' section
Adding an output section to the bash style guidelines

Added some notes about how output should be handled because we were
missing that section and that is very very sad.
Merge pull request #10 from polynomial/output

Adding an output section to the bash style guidelines
Perl is a language that should be avoided (:

Suggest as such in the readme.
Merge pull request #12 from polynomial/perl

Perl is a language that should be avoided (:
Add variable defaulting subsection
Add 'well behaved' function point and examples