Fix cmix package

cmix/client.go

cmix/params.go

cmix/pickup/get.go

cmix/pickup/params.go

cmix/pickup/pickup.go

cmix/pickup/retrieve.go

cmix/pickup/retrieve_test.go

cmix/pickup/roundGetter.go

cmix/pickup/unchecked.go

cmix/pickup/unchecked_test.go

cmix/pickup/utils_test.go