Modify blank? to empty to avoid activesupport/all dependency

Currently the activesupport require doesn't cover all methods used: getting: 

NoMethodError: undefined method `blank?' for #<String:0x007f935c0d7d38>
	/~/.rvm/gems/ruby-1.9.3-p194/gems/garner-0.3.1/lib/garner/strategies/keys/caller_strategy.rb:23:in `block in apply'
	/~/.rvm/gems/ruby-1.9.3-p194/gems/garner-0.3.1/lib/garner/strategies/keys/caller_strategy.rb:19:in `each'
	/~/.rvm/gems/ruby-1.9.3-p194/gems/garner-0.3.1/lib/garner/strategies/keys/caller_strategy.rb:19:in `apply'


Either do this or change require to add either

     require 'active_support/all'

     require 'active_support/core_ext/object/'

or 

     require 'active_support/core_ext/object/blank'