Check for model failure with zero initialization, including tests
Merge branch 'develop' of github.com:stan-dev/stan into develop
Added initialization checks to user-specified initialization, updated tests.
Merge branch 'develop' into feature/robust_zero_init
Unified sampler output through mcmc_writer, updating output to include more information in samples.csv as well as introducing an explicit diagnostic dump option.  Tested and freshly merged with develop.
Unified sampler output through mcmc_writer, updating output to include more information in samples.csv as well as introducing an explicit diagnostic dump option.  Tested and freshly merged with develop.
sort_asc and sort_desc: removed unecessary size vector checks and added some unit tests
Fixed rank(v,s) unit test warning of implicit convertion from double to int.
Merge pull request #81 from stan-dev/feature/new_mcmc_writer

Feature/new mcmc writer
Merge pull request #74 from stan-dev/feature/robust_zero_init

Check for model failure with zero initialization, including tests
Merge pull request #86 from randommm/feature/sort

sort and rank improvements
added include of <string> in ast.hpp
Merge branch 'develop' of https://github.com/stan-dev/stan into feature/fix-grammar-assoc-expected-op