Some examples of code that could be replaced by nidmresults functions

[chrisgorgo]

After discussion at NIDM sprint we decided to implement easy to use functions for common NIDM Results queries. This should lower the access barrier for new developer. Those functions can live in the nidmresults package. They could immediately replace some sparql queries in NeuroVault and nidmviewer (maintained by @vsoch).

get_statmaps() https://github.com/NeuroVault/NeuroVault/blob/0ba7f42a11d703ee608317fe7f0c24fd62d48fc5/neurovault/apps/statmaps/nidm_results.py#L64
as well as https://github.com/vsoch/nidmviewer/blob/882f5201354135ff4dc6ec8739621a94341d0fef/nidmviewer/sparql.py#L43
(this could be split into more functions if that makes sense)

get_coordinates()
https://github.com/vsoch/nidmviewer/blob/882f5201354135ff4dc6ec8739621a94341d0fef/nidmviewer/sparql.py#L28

[cmaumet]

Thanks @chrisfilo! This is related to #12.

[cmaumet]

Reading peaks and statistic map form a NIDM-Results document is now implemented, cf. bin/reader in #29 for an example of usage. I have left #29 open so that we can adapt these functions to make them as easy as possible to use from NeuroVault. Let me know what you think!