LIVY-80. Add blurb in README about upgrading from 0.1.
LIVY-80. Add blurb in README about upgrading from 0.1.

Closes #134

ajbozarth/incubator-livy,ajbozarth/incubator-livy,meisam/incubator-livy,ajbozarth/incubator-livy,ajbozarth/incubator-livy,meisam/incubator-livy,meisam/incubator-livy,ajbozarth/incubator-livy,meisam/incubator-livy,ajbozarth/incubator-livy,meisam/incubator-livy,meisam/incubator-livy