== DESCRIPTION: * Adds +, -, and & methods to Hashes == SYNOPSIS: require 'rubygems' require 'hash_set_operators' {:controller => :user, :action => :edit} + {:action => :show, :id => 1} # => {:controller => :user, :action => :show, :id => 1} {:controller => :user, :action => :edit} - {:action => :show, :id => 1} # => {:controller => :user} {:controller => :user, :action => :edit} & {:action => :show, :id => 1} # => {:action => :edit} == INSTALL: