Remove Travis build status badge from readme

Now that the Travis configuration has been removed, the corresponding status
badge is actively misleading, so I've removed it. There's already a build
status badge for AppVeyor, which now handles all jpy's CI/CD builds.

README.md

@@ -1,4 +1,3 @@
-[![Build Status](https://travis-ci.org/bcdev/jpy.svg?branch=master)](https://travis-ci.org/bcdev/jpy)
 [![Build Status](https://ci.appveyor.com/api/projects/status/ywkcey4nlt0avasf?svg=true)](https://ci.appveyor.com/project/bcdev/jpy)
 [![Documentation Status](https://readthedocs.org/projects/jpy/badge/?version=latest)](http://jpy.readthedocs.org/en/latest/?badge=latest)