Fix issue #74, forbid farray slice steps
Fix issue #74, forbid farray slice steps

sschnug/pyeda,karissa/pyeda,GtTmy/pyeda,pombredanne/pyeda,pombredanne/pyeda,karissa/pyeda,karissa/pyeda,GtTmy/pyeda,pombredanne/pyeda,GtTmy/pyeda,cjdrake/pyeda,sschnug/pyeda,cjdrake/pyeda,cjdrake/pyeda,sschnug/pyeda