TST: Add sample_file tests
Squashed 'pystan/stan/' changes from ae26c9b..0dc2d86

3c47799 Merge pull request #324 from stan-dev/hotfix/v2.0.1
1fb9d1d updating artifacts to v2.0.1
994201a updating makefile to not clean built manual and doxygen doc when running clean-all
cbc3c1a updating version numbers from v2.0.0 to v2.0.1
5c9a45c Merge pull request #322 from stan-dev/feature/issue-292-manual-fixes-2.0.1
0e3fc8c Merge pull request #308 from stan-dev/feature/issue-299-fix-multinormal
d90361a make all suggested updates to manual, fixing issue #292
a8aa2c3 finishes fix for issue #299 -- unit tests for gradients of multi_normal
1b8a3d4 broke multi_normal into component distributions by file with tests broken out
205279f Merge branch 'hotfix/v1.0.1' into feature/issue-299-fix-multinormal
0a881a0 Merge branch 'hotfix/v2.0.1' of https://github.com/stan-dev/stan into hotfix/v2.0.1
72193e6 fixed multi_normal tests ONLY ONE FUNCTION SIGNATURE; fixes OTHER half of #299
8ed83cd fixed multi_normal ONLY ONE FUNCTION SIGNATURE; fixes half of #299
821381e Merge pull request #302 from stan-dev/hotfix/issue-295-diagnose_not_working
ccac040 changed the test_grad call in util to match the test_grad call in v1.3
0f50c0b fixed generated code, updated the call to finite_diff_grad from src/stan/model/util.hpp, added unit test for finite_diff_grad
3e4ec16 Merge pull request #290 from stan-dev/feature/remove_artifacts
70efc09 removing stan-reference-2.0.0.pdf and doxygen from develop.
1afd27c Merge branch 'release/v2.0.0' into develop

git-subtree-dir: pystan/stan
git-subtree-split: 0dc2d867b57e87e5e0232188d868ca9453b53d0d
Stan version 2.0.1 is a patch release. Release addresses the problem with the
multi_normal distribution causing slow sampling.

Merge commit 'aecff3a8ea6a26d3bb1adc99444293c76f0190cc' into develop
Travis-ci fiddling
Release 2.0.1.0