Replace the control flow keywords "and" and "or" with boolean operators && and ||

Replace the control flow keywords "and" and "or" with the boolean operators && and ||. It's just a safer practice. For instance, GitHub's Ruby style guide (https://github.com/styleguide/ruby) says "The and and or keywords are banned. It's just not worth it. Always use && and || instead." Read http://devblog.avdi.org/2010/08/02/using-and-and-or-in-ruby/ for more rationale.

For your consideration :).