Add support for reading and parsing conda build recipes

Following the discussion on bob.admin#35 (closed) and some offline discussion with @andre.anjos, we want to move all our CI infrastructure and packages to conda. This will cause some duplication of information that you would have both in the conda recipe and in the setup.py file.

To keep only one source of information, we decided to make the meta.yaml the authoritative source of information. This means that we populate the information in setup.py from the meta.yaml file. Here is a list of tasks or information that should be gotten from meta.yaml file:

• bob.extension will use pyyaml and jinja2 to parse the yaml file
• Make CONDA_BUILD=0 in the jinja2 context parser to get only the PyPI requirements.
• Accomodate for name differences between conda packages and PyPI package names if any
• package name
• package version
• package PyPI requirements
• console entry points
• home website
• license
• short description
• setup_requires
• install_requires
• test_requires

Maybe we can have a function in bob.extension that reads the yaml file and returns this information in a dictionary format.