Add yaml file for controlling the continuous integration service.

 * This is currently hooked to my personal repo, for testing purposes, before
   we decide whether or not to hook it to the common organization repo.
 * The continuous integration is pretty basic so far: it checks with python
   versions 2.6, 2.7, and 3.3, that we are able to install everything in the
   requirements.txt file, that "$ ./inputs/make" works, and then that the
   following test:
   "$ bin/ooniprobe nettests/blocking/dnsconsistency.py \
        -f inputs/ooni-inputs/processed/alexa-top-1k.txt"
   completes successfully.
 * It uses Travis-CI, see http://about.travis-ci.org/docs/user/getting-started/
Add --use-mirrors to the TravisCI install command, as is recommended.
Oops. 'make' should be run from the ./inputs/ directory, it's not a script. Duh.
Update .travis.yml to copy the ooniprobe.conf.sample to ooniprobe.conf.

 * Fixes #8450.
Use example_inputs in .travis.yml rather than ooni_inputs.

 * Fixes #8451

travis-lint checks out properly:
(ooni)∃!isisⒶwintermute:~/code/torproject/ooni-probe ∴ travis-lint
Hooray, /home/isis/code/torproject/ooni-probe/.travis.yml seems to be solid!

(ooni)∃!isisⒶwintermute:~/code/torproject/ooni-probe ∴ date
Mon Mar 11 20:22:20 UTC 2013
Add travis-ci build script.
(cherry picked from commit cfe357a546669c3ca70ee1f65dbc5034c2be4760)
Update .travis.yml to put the install commands under the install section.

 * Separate commands for testing pip and setuptools installations.
 * TODO I believe there is a way to tell TravisCI to try both, we should check
   the docs.

travis-lint results:
(ooni)∃!isisⒶwintermute:~/code/torproject/ooni-probe ∴ travis-lint
Hooray, /home/isis/code/torproject/ooni-probe/.travis.yml seems to be solid!
(ooni)∃!isisⒶwintermute:~/code/torproject/ooni-probe ∴ date
Mon Mar 11 21:00:27 UTC 2013
Merge pull request #67 from isislovecruft/feature/continuous-integration

Feature/continuous integration
Merge branch 'master' into develop