Merge: Automatic testing of NIDM export in SPM

This pull request allows to automatically test that the NIDM export stored in `nidm/nidm-results/test/spmexport/example001` is consistent with `nidm-results.owl` and is identical to the gold standard specified in `nidm/nidm-results/spm/example001`. 

Automatic testing is done using Travis CI as discussed in #106.