elastic v0.7.8

NEW FEATURES

• New function docs_update() to do partial document updates (#152)
• New function docs_bulk_prep() to prepare bulk format files
  that you can use to load into Elasticsearch with this package, on the
  command line, or in any other context (Python, Ruby, etc.) (#154)

MINOR IMPROVEMENTS

• We're no longer running a check that your ES server is up before
  every request to the server. This makes request faster, but may lead to
  less informative errors when your server is down or in some other state
  than fully operational (#149)
• Tweaks here and there to make sure elastic works with Elasticsearch
  v5. Note that not all v5 features are included here yet. (#153)

BUG FIXES

• docs_bulk() was not working on single column data.frame's. now is
  working. (#151) thanks @gustavobio
• docs_* functions now support ids with whitespace in them. (#155)
• fixes to docs_mget() to fix requesting certain fields back.