Conda

Improvements
* use install.rm_rf for TemporaryDirectory cleanup (3425)
* improve handling of local dependency information (2107)
* add default channels to exports for Windows and Unix (4103)
* make subdir configurable (4178)

Bug Fixes
* fix conda/install.py single-file behavior (3854)
* fix the api->conda substitution (3456)
* fix silent directory removal (3730)
* fix location of temporary hard links of index.json (3975)
* fix potential errors in multi-channel export and offline clone (3995)
* fix auxlib/packaging, git hashes are not limited to 7 characters (4189)
* fix compatibility with requests >=2.12, add pyopenssl as dependency (4059)
* fix 3287 activate in 4.1-4.2.3 clobbers non-conda PATH changes (4211)

Non-User-Facing Changes
* fix open-ended test failures relating to python 3.6 release (4166)
* allow args passed to cli.main() (4193, 4200, 4201)
* test against python 3.6 (4197)

Deprecations/Breaking Changes
* show warning message for pre-link scripts (3727)
* error and exit for install of packages that require conda minimum version 4.3 (3726)

Improvements
* double/extend http timeouts (3831)
* let descriptive http errors cover more http exceptions (3834)
* backport some conda-build configuration (3875)

Bug Fixes
* fix conda/install.py single-file behavior (3854)
* fix the api->conda substitution (3456)
* fix silent directory removal (3730)
* fix 3910 null check for is_url (3931)

Non-User-Facing Changes
* flake8 E116, E121, & E123 enabled (3883)

Bug Fixes

* fix 3732, 3471, 3744 CONDA_BLD_PATH (3747)
* fix 3717 allow no-name channels (3748)
* fix 3738 move conda-env to ruamel_yaml (3740)
* fix conda-env entry point (3745 via 3743)
* fix again 3664 trash emptying (3746)

Improvements
* only try once for windows trash removal (3698)

Bug Fixes
* fix anaconda api token bug (3674)
* fix 3646 FileMode enum comparison (3683)
* fix 3517 conda install --mkdir (3684)
* fix 3560 hack anaconda token coverup on conda info (3686)
* fix 3469 alias envs_path to envs_dirs (3685)

Improvements
* add json output for `conda info -s` (3588)
* ignore certain binary prefixes on windows (3539)
* allow conda config files to have .yaml extensions or 'condarc' anywhere in filename (3633)

Bug Fixes
* fix conda-build's handle_proxy_407 import (3666)
* fix 3442, 3459, 3481, 3531, 3548 multiple networking and auth issues (3550)
* add back linux-ppc64le subdir support (3584)
* fix 3600 ensure links are removed when unlinking (3625)
* fix 3602 search channels by platform (3629)
* fix duplicated packages when updating environment (3563)
* fix 3590 exception when parsing invalid yaml (3593 via 3634)
* fix 3655 a string decoding error (3656)

Non-User-Facing Changes
* backport conda.exports module to 4.2.x (3654)
* travis-ci OSX fix (3615 via 3657)

Bug Fixes
* fix 3536 conda-env messaging to stdout with --json flag (3537)
* fix 3525 writing to sys.stdout with --json flag for post-link scripts (3538)
* fix 3492 make NULL falsey with python 3 (3524)