Changes for clojure.contrib.string/escape

abhi on Tue, 15 May 2012
(clojure.string/escape "asdf" {\a \b}) 
=> "bsdf"
(clojure.string/escape "asdf" {\a "b"}) 
=> "bsdf"
(clojure.string/escape "asdf" {\a "bb"}) 
=> "bbsdf"