Initial work on the NIEC mods extension.
Implement more of the specification.  Also, add a private helper method to avoid rewriting the namespace_prefix/eventually the Solrization information x1000 times.
Accidentally set the expected namespace of the mods:extension element containing NIEC data to niec - reverting.
Hook NIEC extension into the actual MODS datastream correctly.
Unify getter/setter method creation under a single :nattr (nested attribute (maybe not a great name)) class method - eliminates lots of ugly boilerplate code, tbf replaces it with other ugly boilerplate code.
Programmatically generate solr response for the niec element, complete boilerplate for nested setter/getter access.
Elementary solrization tests and basic setter/getter sanity checking.
If '2014' is a valid entry for the publicationDate format, this field isn't storable as a Solr date field.  Since I assume all of the date fields in the NIEC extension are as loosely constrained, I've moved them over to string storage for the time being.
Add a NIEC fixture file for potential future testing - insert NIEC Solr Hash generation into the mods #to_solr method.
Merging wills niec code. Just a minor revision of mods datastream required.