rdryad 0.2.0

NEW FEATURES

• Re-worked most of the package.
• New package API, some methods are the same, but many are different. (#16)
• New functions (see functions starting with d_*()) to interact
  with Dryad Solr search engine (#10)
• OAI-PMH functions now using internally the oai package. (#14)

MINOR IMPROVEMENTS

• Slimmed down dependencies to a smaller set.
• Changed license from CC0 to MIT (#17)
• Added more tests (#18)
• Changed function to get files to only download them, and not attempt to
  read them into R, which introduces a very long dependency chain (#15)