.travis.yml: Configure Travis CI for automated testing

The installation instructions are based on the Ubuntu 12.04
instructions [1].  Conveniently for us, Travis uses Ubuntu 12.04 as
its Linux environment as well [2].  I made a few changes to the
suggested installation procedure:

* build-essential [3] instead of g++ (so we get Make too)
* Non-Python [4] RDKit from packages [5,6,7,8,9] instead of from
  source, although this installs RDKit v201106, which may be too old?
  I haven't checked any of the InChl stuff [10] for building from
  source, so this might be completely broken at the moment.
  Unfortunately, the version of RDKit on PyPI is 2009.Q1b1, which is
  too old for the libraries we've installed from packages [11].
* Travis doesn't support Python 2.5 [12], so I only test on 2.6 and
  2.7.

I also don't understand how RMG-Py finds RMG-database, so that might
be broken as well.

[1]: http://greengroup.github.io/RMG-Py/users/rmg/installation/linux.html
[2]: http://docs.travis-ci.com/user/installing-dependencies/#Installing-Ubuntu-packages
[3]: http://packages.ubuntu.com/precise/build-essential
[4]: http://docs.travis-ci.com/user/languages/python/#Travis-CI-Uses-Isolated-virtualenvs
[5]: http://www.rdkit.org/docs/Install.html#ubuntu-12-04-and-later
[6]: http://packages.ubuntu.com/precise/python-rdkit
[7]: http://packages.ubuntu.com/precise/librdkit-dev
[8]: http://packages.ubuntu.com/precise/librdkit1
[9]: http://packages.ubuntu.com/precise/rdkit-data
[10]: http://code.google.com/p/rdkit/wiki/BuildingWithCmake#Getting_Ready
[11]: https://pypi.python.org/pypi/rdkit
[12]: http://docs.travis-ci.com/user/languages/python/#Choosing-Python-versions-to-test-against

.travis.yml

@@ -0,0 +1,15 @@
+language: python
+python:
+  - "2.6"
+  - "2.7"
+before_install:
+  - sudo apt-get update -qq
+  - sudo apt-get install git build-essential gfortran python-dev liblapack-dev python-openbabel python-setuptools python-pip
+  - sudo apt-get install python-rdkit librdkit-dev librdkit1 rdkit-data
+  - git clone [email protected]:GreenGroup/RMG-database.git
+install:
+  - pip install numpy --use-mirrors
+  - pip install -r requirements.txt --use-mirrors
+  - make
+  - pip install .
+script: make test