gcd.clj problem updates: changed training case generators to make them harder to guess; slight mods to genetic operators; recorded some successful programs as comments
gcd.clj problem updates: changed training case generators to make them harder to guess; slight mods to genetic operators; recorded some successful programs as comments

lspector/Clojush,thelmuth/Clojush,thelmuth/Clojush,lspector/Clojush