Remove errant logging message about chain number

Rely on stan::common for this kind of reporting.
Fix argument handling for HMC
Fix corner case when calculating number of digits in summary
Report chain number in progress
Squashed 'pystan/stan/' changes from 3ba4dcc..3c0cf62

3c0cf62 Merge pull request #840 from stan-dev/feature/issue-768-interruptions-for-bfgs
c59d97a Merge pull request #851 from stan-dev/feature/issue-850-erf-nan-input
6bd2779 updating call to error handling to use C++ style static_cast instead of C style cast
3b54c4d fixes #850. throws exception on nan input
92c6688 adding failing Phi test for src/stan/math/functions/Phi.hpp
9067cb7 Merge pull request #842 from stan-dev/feature/issue-841-move-tests
6224204 moved test to src/test/unit/math/functions/sign_test.cpp
3c6055a added callback for do_bfgs_optimize at every iteration
5384b34 Merge pull request #837 from stan-dev/bugfix/issue-835-fix-exp-precedence
06d298f Merge pull request #832 from stan-dev/feature/issue-683-size-0-input
e35a8ba Merge pull request #820 from stan-dev/feature/issue-577-modulus-operation
37490e3 fixed bug, model compiles, runs, verified cacluations by hand
e431122 Merge pull request #802 from stan-dev/feature/issue-748-stmt-raise-exception
bc5f5b1 added precedence test, exp vs index operator, test fails
17ff6d7 Merge pull request #829 from stan-dev/feature/issue-828-move-check-range
1725c4c Merge branch 'develop' into feature/issue-748-stmt-raise-exception
3ea77d9 fixed dump to accept zero-length arrays and vectors
343b552 Merge branch 'develop' of https://github.com/stan-dev/stan into develop
2f71a77 move check_range to math/error_handling/matrix
a9d1fa8 Merge pull request #825 from alyst/doc-frechet-weibull
b355040 document Frechet and Weibull distributions relation
101f065 Update and rename int_divide_test.cpp to divide_test.cpp
4782053 function int_divide now called divide, warning message for int division reinstated, unit tests updated accordingly
43e5b78 Merge pull request #807 from stan-dev/feature/frechet-distr
f4bf123 more division tests
4336157 added/renamed unit test file
72dceb6 modified per pull request comments
c8e1550 made int division behaviour consistent w/ modulus, modified unit tests, unit tests for parser split into groups of related tests
9a1c16a fixed lower bound test for frechet distr
1f7680e switch to check_positive_finite in frechet distr file
1f824cc merge develop
a9d4bf3 Merge pull request #809 from stan-dev/feature/issue-800-check-positive-finite
19db7c3 merging w/ develop to pick up changes to unit tests for gm/parser
a2868a5 updated language reference
5d2689f Merge pull request #814 from stan-dev/feature/issue-640-update-error-message
6cd1daa Merge branch 'develop' into feature/issue-800-check-positive-finite
805f2da Merge branch 'develop' into feature/frechet-distr
edc420f remove unused code and fixed frechet test
8492aaa modulus working, added unit tests
0f6a31c added modulus rule
d5a6af7 Merge pull request #816 from stan-dev/feature/issue-815-check_simplex-message
dc63d09 unit tests under test/unit/gm/raise_exception, models under test-models/no-main/gm/raise_exception
c81325c cleanup
5f52752 updated stan reference
141560e updating test -- Windows wasn't initializing to 0
5cd72c1 adding more precision to error message
0310041 added code and tests to handle multiple args to raise_exception stmt
3519975 Merge branch 'develop' of https://github.com/stan-dev/stan into develop
0f80105 updating error message within check_simplex
eab8da9 fixed bug for raise_exception statement with multiple args
3feab5c Merge branch 'develop' into feature/frechet-distr
7198732 removed .orig file
b7c677a fix merge conflict
81004ab Merge pull request #813 from ariddell/feature/typo
b39f273 Remedy typo
44c8da7 removed confusing 'Error in function' from exceptions
d7fd71b Merge pull request #808 from stan-dev/feature/multi-gp-cholesky
808c00b Merge pull request #798 from stan-dev/feature/issue-796-unused-function-warning-gcc
abd12f7 added frechet_rng test against quantiles generated in R
ac2f1b9 add missing include
8c8bf50 fixed missing using statement
9ab0dcc replace check_positive and check_finite with check_positive_finite
d7e192a add check_positive_finite with tests
3bbad83 Merge branch 'develop' into feature/frechet-distr
cae9b67 Merge branch 'develop' into feature/multi-gp-cholesky
8afc0a3 Merge pull request #790 from stan-dev/feature/issue-787-cbind-rbind
276e890 fix merge conflict
905f2e6 merge changes
68b09c9 merge alyst changes
232e4f9 moved distribution function signature test
23c04b3 merge frechet
52668d7 Revert "merge changes from alyst"
e5e6ed5 merge changes from alyst
cdb33fb added append_row and append_col to parser_tests
92150e0 Merge branch 'develop' into feature/issue-787-cbind-rbind
ef4c13a Merge pull request #791 from stan-dev/feature/function-sig-tests
dde5504 tests for correct behaviour in all stan program blocks
d4dfa5f tests for called from transformed data block, all tests call model directly
432dfac Added integer division function
d59e64a Added modulus function
6677371 updated split out parser tests after merge
4c5f92d merge conflict
551b61c Merge pull request #785 from stan-dev/bugfix/issue-579-vec-to-array-msg
46602e8 Fix wrong test names
0138939 test function that raises exception, called from model block
1df5e20 test that exception is thown in model block by calling that block (i.e. model's log_prob method) directly
04a9435 Removed unused variable match_index
c313244 Added inline to recover_memory() and free_memory() to avoid warnings in gcc
d305083 Renamed cbind and rbind to append_col and append_row, respectively
77923fd add _rng test for Frechet distribution
ef5a0b2 Merge branch 'develop' into feature/issue-787-cbind-rbind
822fce3 Fixed typo in rbind documentation as was pointed out by Peter Li
222158c split out parser_test
9380ddd Added documentation for cbind and rbind + minor fix for Transposition Postfix Operator documentation
7f12766 Fix incorrect reference to inverse in to_matrix function signature test
09a0178 Minor improments to rbind and cbind
a2966a5 Added cbind and rbind to function signatures and related signature tests
1bc2a36 Some basic fwd-rev tests for cbind and rbind
17e6d99 Merge pull request #783 from stan-dev/feature/issue-782-improvement-to-gp-fit.stan
1000841 Merge pull request #780 from stan-dev/feature/issue-578-header-guard-format
49e26c1 Merge pull request #777 from stan-dev/feature/issue-776-remove-leading-underscore-mcmc
2cb614e rbind: functions with correct promotion of args and added agrad-rev tests
65cfa58 cbind: functions with correct promotion of args and added agrad-rev tests
dea5b3d add function signatures tests for Frechet distribution
07797cc add multi_gp_cholesky syntax tests
808cf32 Extra test to cbind and rbind
9ea743e Added rbind functions and tests
8db4780 Added cbind functions and tests
0ab877d add multi_gp_cholesky distribution
13e7a52 add Frechet distribution
2adcb73 cosmetics for Weibull
eb981cf cleanup multi_gp
bd901da use dedicated variable for Cholesky factor in tests
39c2c46 sync multi_normal and multi_normal_cholesky
23b5fd4 fix multi_gp_log() signature in doc
8901c03 cleanup - wrong branch for these test models
f678f1e stan models that test error detection, error message
6359f72 cleanup - code for raise_exception stmts should be in branch issue-748, not in this one.
0458255 issue 782: stan/src/models/misc/gaussian-process/gp-fit.stan will be the same as the model written in the manual
63cab3d Merge branch 'develop' of https://github.com/stan-dev/stan into develop
18198c3 adding tests for model block behaviors
c42762c switched order of error checks, made error messages more consistent, updated unit test
61a3bf5 Remove leading and trailing underscores from header guards
1abc071 Fix scope bug
f991b97 test raise exception in model block
9fc8cae moved tests for raise exception to no-main
f3b49f8 Remove leading underscores from src/stan/mcmc classes and corresponding tests
3c49f00 added tests for functions which throw exceptions
66a359f added models for integration test
6b99221 added raise_exception, compiles, tested by hand
f71cd8a Merge branch 'develop' of https://github.com/stan-dev/stan into develop
7cbce37 Merge branch 'develop' of https://github.com/stan-dev/stan into develop

git-subtree-dir: pystan/stan
git-subtree-split: 3c0cf621fce23aa20da8999f323c933021a0a87c
Merge commit 'cae205ce8df9b541797a3c43702af766dfe4d3da' into unstable
Support checking for user interrupt during optimizing

Closes #93