Automatic creation of NIDM-Results specification from nidm-results.owl file (now in Python)

Following discussions with @dbkeator, in this pull request you will find a new script `OwlSpecification.py` that:

- Generate a ReSpec-like section describing classes and attributes as stored in `nidm-results.owl` file (similarly to what was intially done for the HBM Hackathon 2014 using google scripts).

- Merge this automatically-generated section with `include/nidm-results_head.html` and `include/nidm-results_foot.html` (those two files can be manually edited as needed).

(This solves some of the issues reported in #67.)

@dbkeator: Could you let me know what you think? Thanks in advance!