Don't use shields.io for Travis or bintray badges

Shields.io seems to be flakey for bintray badge. See
badges/shields#658

Travis CI has an identical looking badge, so might as well go direct for it as
well.

Author: xenomachina

README.md

@@ -1,8 +1,8 @@
 # ![Kotlin --argparser](https://rawgit.com/xenomachina/kotlin-argparser/master/logo.svg)
 
-[ ![Download from bintray](https://img.shields.io/bintray/v/xenomachina/maven/kotlin-argparser.svg?style=plastic) ](https://bintray.com/xenomachina/maven/kotlin-argparser/%5FlatestVersion)
-[ ![Travis CI](https://img.shields.io/travis/xenomachina/kotlin-argparser.svg?style=plastic) ](https://travis-ci.org/xenomachina/kotlin-argparser)
-[ ![License: LGPL 2.1](https://img.shields.io/badge/license-LGPL--2.1-blue.svg?style=plastic) ](https://www.gnu.org/licenses/old-licenses/lgpl-2.1.en.html)
+[![Download](https://api.bintray.com/packages/xenomachina/maven/kotlin-argparser/images/download.svg) ](https://bintray.com/xenomachina/maven/kotlin-argparser/%5FlatestVersion)
+[![Build Status](https://travis-ci.org/xenomachina/kotlin-argparser.svg?branch=master)](https://travis-ci.org/xenomachina/kotlin-argparser)
+[![License: LGPL 2.1](https://img.shields.io/badge/license-LGPL--2.1-blue.svg) ](https://www.gnu.org/licenses/old-licenses/lgpl-2.1.en.html)
 
 This is a library for parsing command-line arguments.  It can parse both
 options and positional arguments.  It aims to be easy to use and concise yet