Fix a minor style issue
Merge pull request #45 from frewsxcv/patch-2

Fix a minor style issue
Include request exception traceback in log

- When an exception occurs when handling a request, the exception
  message is sent back to Neovim and appended as a warning in the,
  log - this commit uses the traceback in the log instead
Support Buffer.__delitem__()
Merge pull request #47 from equalsraf/tb-traceback

Include request exception traceback in log
Merge pull request #48 from equalsraf/tb-buffer-delitem

Support Buffer.__delitem__()
Use $VIM in runtimepath test.
Merge pull request #51 from fwalch/rtp-test

Use $VIM in runtimepath test.
Travis: Use Neovim nightly and separate flake jobs.