Fixing ValueError in _split_data
Merge pull request #120 from jrings/develop

Fixed an error in _split_data
Update Stan source
Eliminate compilation of libstan.a, use Stan library "header-only"
BUG: Fix bug where pickling of fit objects fails without error.

Pickling fit objects still does not work as desired. As a short term fix,
issue a warning telling users that if they have the model pickled as well,
all should work.
CI: disable travis OS X testing as it is currently broken
TST: Update stanc parser errors
ENH: Silence confusing (ignored) exceptions about model._temp_dir
TST: Improve test of pickling fit objects
BUG: Fixes problem displaying legitimate `nan` results in fit summary

Closes #123
Minor code cleanup and removal of unused variable
TST: Minor adjustment to pickling tests for travis-ci
Merge branch 'feature/pickling-work' into develop
Release PyStan 2.5.0.1
DOC: Patch for Read the Docs