Added Travis CI configuration file, build status icon, and setup script.

It's convenient for checking product's build status.

First, I have confirmed two case failed.
https://travis-ci.org/zaneli/memcontinuationed/jobs/24579299#L963

    [error] 	com.dongxiguo.memcontinuationed.GetsTest
    [error] 	com.dongxiguo.memcontinuationed.GetTest

I found the two approaches to fix it.

One approach is specified `parallelExecution in Test := false` in build.sbt.
And other one is using another key in GetTest and GetsTest.
I chose the latter.
But if you think the former is desirable, I'll modify and re-push this pull request.

I modified GetsTest and confirmed build success at my repository.
https://travis-ci.org/zaneli/memcontinuationed/builds/24596134
[![Build Status](https://travis-ci.org/zaneli/memcontinuationed.png?branch=travis-ci)](https://travis-ci.org/zaneli/memcontinuationed)