Added exec_string_iterate instruction
Added exec_string_iterate instruction

thelmuth/Clojush,Vaguery/Clojush,NicMcPhee/Clojush,thelmuth/Clojush,lspector/Clojush,NicMcPhee/Clojush,Vaguery/Clojush,lspector/Clojush,saulshanabrook/Clojush,saulshanabrook/Clojush