.travis.yml: Add pypy
.travis.yml: Add pypy

leepa/isort,levic/isort,tomviner/isort,PyCQA/isort,pahko/isort,jamesbroadhead/isort,adamchainz/isort,jmullan/isort,tomviner/isort,PyCQA/isort,adamchainz/isort,aequitas/isort,jmullan/isort,gforcada/isort,wimglenn/isort,jamesbroadhead/isort,levic/isort,aequitas/isort,wimglenn/isort,AbsoluteMSTR/isort,AbsoluteMSTR/isort,pahko/isort,graingert/isort,gforcada/isort,leepa/isort,graingert/isort