Merge branch 'feature/issue-786-manual-2.5' of https://github.com/stan-dev/stan into feature/issue-786-manual-2.5
Merge branch 'feature/issue-786-manual-2.5' of https://github.com/stan-dev/stan into feature/issue-786-manual-2.5
Merge branch 'feature/issue-786-manual-2.5' of https://github.com/stan-dev/stan into feature/issue-786-manual-2.5
checkpointing after lots of changes