added missing require in proxy pattern

alphabetic order list

added prints of facade pattern

Merge pull request #11 from ID25/facade-pattern

Added Facade Pattern Example

Update iterator.rb

Merge pull request #10 from john-denisov/patch-1

fix typo

fix typo

added fun interpreter pattern

Merge pull request #9 from tadassce/fix_examples

Fix strategy example

Fix state

Add missing require in proxy example

Fix observer