Merge branch 'develop' of https://github.com/stan-dev/stan into develop
Merge branch 'develop' of https://github.com/stan-dev/stan into develop
fixed R script, updated README, polls.dat now has 1 row per survey
Merge pull request #747 from stan-dev/bugfix/issue-742-ARM-Ch2

Fixes #747. Bugfix/issue 747 arm ch2
Merge branch 'develop' into feature/issue-743-von_mises-pi
replaced TWO_PI with 2*stan::math::pi()