small permutations improvement
small permutations improvement

use XOR swap trick, as suggested by timotimo
Gnouc/rakudo,labster/rakudo,awwaiid/rakudo,azawawi/rakudo,jonathanstowe/rakudo,ab5tract/rakudo,b2gills/rakudo,softmoth/rakudo,awwaiid/rakudo,tony-o/rakudo,MasterDuke17/rakudo,nbrown/rakudo,sjn/rakudo,jonathanstowe/rakudo,ugexe/rakudo,MasterDuke17/rakudo,lucasbuchala/rakudo,samcv/rakudo,paultcochrane/rakudo,samcv/rakudo,usev6/rakudo,tony-o/rakudo,b2gills/rakudo,ugexe/rakudo,lucasbuchala/rakudo,ungrim97/rakudo,softmoth/rakudo,LLFourn/rakudo,salortiz/rakudo,tbrowder/rakudo,usev6/rakudo,ungrim97/rakudo,tbrowder/rakudo,tony-o/rakudo,LLFourn/rakudo,labster/rakudo,b2gills/rakudo,b2gills/rakudo,LLFourn/rakudo,softmoth/rakudo,salortiz/rakudo,sjn/rakudo,usev6/rakudo,jonathanstowe/rakudo,MasterDuke17/rakudo,awwaiid/rakudo,MasterDuke17/rakudo,ungrim97/rakudo,paultcochrane/rakudo,salortiz/rakudo,zostay/rakudo,labster/rakudo,azawawi/rakudo,samcv/rakudo,raydiak/rakudo,dankogai/rakudo,raydiak/rakudo,samcv/rakudo,sjn/rakudo,raydiak/rakudo,usev6/rakudo,rakudo/rakudo,dankogai/rakudo,Gnouc/rakudo,ab5tract/rakudo,Gnouc/rakudo,tbrowder/rakudo,sjn/rakudo,LLFourn/rakudo,MasterDuke17/rakudo,dankogai/rakudo,tony-o/rakudo,dankogai/rakudo,Gnouc/rakudo,LLFourn/rakudo,zostay/rakudo,labster/rakudo,dankogai/rakudo,azawawi/rakudo,ab5tract/rakudo,azawawi/rakudo,tbrowder/rakudo,lucasbuchala/rakudo,jonathanstowe/rakudo,salortiz/rakudo,sjn/rakudo,salortiz/rakudo,zostay/rakudo,paultcochrane/rakudo,tony-o/rakudo,paultcochrane/rakudo,labster/rakudo,awwaiid/rakudo,nbrown/rakudo,softmoth/rakudo,azawawi/rakudo,ugexe/rakudo,paultcochrane/rakudo,ab5tract/rakudo,tbrowder/rakudo,MasterDuke17/rakudo,labster/rakudo,ab5tract/rakudo,awwaiid/rakudo,tony-o/rakudo,tbrowder/rakudo,zostay/rakudo,rakudo/rakudo,lucasbuchala/rakudo,usev6/rakudo,b2gills/rakudo,jonathanstowe/rakudo,samcv/rakudo,ugexe/rakudo,rakudo/rakudo,nbrown/rakudo,ugexe/rakudo,nbrown/rakudo,softmoth/rakudo,ungrim97/rakudo,Gnouc/rakudo,nbrown/rakudo,raydiak/rakudo,rakudo/rakudo,nbrown/rakudo,rakudo/rakudo,salortiz/rakudo,ungrim97/rakudo,lucasbuchala/rakudo,rakudo/rakudo,Gnouc/rakudo