Decompose conditional

Adds [decompose conditional](http://sourcemaking.com/refactoring/decompose-conditional) as a refactor encouraged to make ``if`` statements clearer.

@michael-erasmus and I had a quick chat last week via GitHub on f35ad4fb371a59e447f377e68d5099bbf692c330, and he encouraged me to send this PR with those examples (sorry for the delay Michael!).

How do you feel about them? Yay or nay? :)

Excited to hear your thoughts!