Travis CI setup

[Ciro Santilli]

I've made a Travis CI build at:
https://github.com/cirosantilli/binutils-gdb/tree/gdb/travis

It runs in an Ubuntu 12.04 AMD64 machine.

It finishes in 20 minutes with 30 errors:
https://s3.amazonaws.com/archive.travis-ci.org/jobs/72605568/log.txt ,
less than the 46 on my Ubuntu 14.04 machine, and the same Buildbot
commit result.

With parallel tests make -j$(ncpus) it runs in 4 minutes, but the
error rate goes up.

Best of all: free testing infrastructure, that can be used by anyone
to test commits on branches before they are merged.

Let me know if the build steps on the .travis.yml can be improved
somehow to reduce false errors.