Merge pull request #324 from stan-dev/hotfix/v2.0.1

Hotfix/v2.0.1
Merge pull request #461 from stan-dev/release/v2.1.0

Release/v2.1.0
switched to arena malloc to fix #472
added stack_alloc::bytes_allocated and test
added bytes allocated test to softmax test
getting stack_alloc to work under Windows
Merge branch 'master' of https://github.com/stan-dev/stan into hotfix/v2.1.1
Added method to inspect the size of the stack. Added test for softmax checking that all elements were allocated to the correct stack.
Merge branch 'bugfix/issue-472-softmax-leak' of https://github.com/stan-dev/stan into bugfix/issue-472-softmax-leak
changed name from cur_size to bytes_requested in stack_alloc
adding a test that could be used for speed tests
Merge pull request #474 from stan-dev/bugfix/issue-472-softmax-leak

Fixes #472.
Merge branch 'hotfix/v2.1.1' of https://github.com/stan-dev/stan into hotfix/v2.1.1
fixed leak on log_softmax, added brittle test; added code doc to softmax test
got rid of extraneous print in log_softmax test
updated multinomial, fixes #499
removing bytes_allocated function from stack_alloc. The functions that were leaking have already been patched.
Merge branch 'develop' into hotfix/v2.1.1
moving test
Merge pull request #494 from stan-dev/hotfix/v2.1.1

Fixes #472 - memory leaks