Feature/versioneer automatic version bumping and configuration.

This mostly consists of this:
```
* commit 671a46af7d19a2473b507a22124016a0f87ee63d
| gpg: Signature made Thu 06 Jun 2013 12:59:57 UTC
gpg:                using RSA key A3ADB67A2CDB8B35
gpg: Good signature from "Isis! <isis@patternsinthevoid.net>" [ultimate]
gpg:                 aka "Isis <isis@leap.se>" [ultimate]
gpg:                 aka "Isis <isis@torproject.org>" [ultimate]
gpg:                 aka "Isis! <isis@riseup.net>" [ultimate]
gpg: Signature notation: isis@patternsinthevoid.net=0A6A58A14B5946ABDE18E207A3ADB67A2CDB8B35
gpg: Signature expires Fri 06 Jun 2014 12:59:57 UTC
Author:     Isis Lovecruft <isis@torproject.org>
| AuthorDate: 4 hours ago
| Commit:     Isis Lovecruft <isis@torproject.org>
| CommitDate: 4 hours ago
| 
|     Add versioneer to automatically generate oonib version numbers.
|     
|      * When a release is made, the tag MUST be prefixed correctly. To make a
|        release, do:
|     
|        $ git checkout -b release-1.2.3
|        [run some integration tests and other QA...]
|        [write a CHANGELOG entry...]
|        [you can make commits with minor fixes here too]
|        $ git tag -a oonib-1.2.3 -s
|        $ git push
|        $ git push --tags
|        $ git checkout master
|        $ git merge -S --no-ff release-1.2.3
|        $ git checkout develop
|        $ git merge -S --no-ff release-1.2.3
|        $ git branch -d release-1.2.3
|        $ python setup.py register sdist upload
|     
|        The version will automagically get bumped according to the number in the
|        git tag. Additionally, if builds are created from a dirty repo, or with
|        HEAD not at the commit of a signed tag, the last bit of the commit hash
|        will be appended to the major version number so that we know precisely
|        where the build came from.
| 
|  .gitattributes    |    1 +
|  oonib/__init__.py |    4 +
|  oonib/_version.py |  197 +++++++++++++++++++++++++++++++++++++++
|  versioneer.py     |  656 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
|  4 files changed, 858 insertions(+)
```

NOTE: the commands in that commit are now different, I changed them a bit so that for a release of ooni-backend, one should do a different tag name (starting with ´v´ to match ooni-probe):

```
|        $ git checkout -b release-1.2.3
|        [run some integration tests and other QA...]
|        [write a CHANGELOG entry...]
|        [you can make commits with minor fixes here too]
|        $ git tag -a v1.2.3 -s
|        $ git push
|        $ git push --tags
|        $ git checkout master
|        $ git merge -S --no-ff release-1.2.3
|        $ git checkout develop
|        $ git merge -S --no-ff release-1.2.3
|        $ git branch -d release-1.2.3
|        $ python setup.py register sdist upload
```