Move files into a GDor::Indexer module for ease of reuse
Create a SolrDocHash class instead of monkey-patching Hash
Move data validation into the solr doc hash model
Refactor field_present?
Separate exception handling from processing (so tests can report useful failures)
Update to rspec 3-style syntax
Refactor SolrDocHash#combine
Stub RSolr.add
Fix up model validation checking
Provide a friendlier error message when not running under jruby
Update rspec and equivalent-xml