Further attempts to fix CI (failing)

I tried a lot of things to fix the CI build. I played with vagrant, but i could not reproduce the errors (staling build before the first test case and error 137). For some reason, it still showed the usage statistics dialog. But i think that is not the problem in Travis, since the usage would stale the build after all tests run, it does not effect the test cases.

I also updated the plugins to work with JDK8, and switched to JDK8 in Travis.

I updated the build-tools because right now we used a stale version which was not installed. This is the only real problem this PR fixes.

So this PR cannot fix the CI, but i think it still holds valuable additions, maybe can be merged, or cherry-picked. I have to say i am really embittered about the CI, but @rgladwell spent three days on that...
If somebody builds with older maven version, the build fails, also the
versions plugin can correctly print new plugin updates with the
display-plugin-updtates goal.
On Nov 4, 2014 2:27 PM, "Ricardo Gladwell" <notifications@github.com> wrote:

> In pom.xml:
>
> > @@ -45,6 +45,10 @@
> >      <system>Travis</system>
> >    </ciManagement>
> >
> > +  <prerequisites>
>
> What does this do?
>
> --
> Reply to this email directly or view it on GitHub
> <https://github.com/rgladwell/m2e-android/pull/278/files#r19801784>.
>