add --recursive to install from source

since stan is a submodule, --recursive is necessary to do a clean install from source
Merge pull request #114 from kforeman/patch-1

add --recursive to install from source
DOC: remove reference to non-existent parameter tol_rel_param
DOC: simplify release instructions
Disable multiprocessing when there is only one chain
Update Stan source to v2.5.0
Add AUTHORS
Update for release of 2.5.0.0
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