New Features
* **New Configuration Engine**: Configuration and "operating context" are the foundation of
conda's functionality. Conda now has the ability to pull configuration information from a
multitude of on-disk locations, including `.d` directories and a `.condarc` file *within*
a conda environment), along with full `CONDA_` environment variable support. Helpful
validation errors are given for improperly-specified configuration. Full documentation
updates pending. (2537, 3160, 3178)
* **New Exception Handling Engine**: Previous releases followed a pattern of premature exiting
(with hard calls to `sys.exit()` when exceptional circumstances were encountered. This
release replaces over 100 `sys.exit` calls with python exceptions. For conda developers,
this will result in tests that are easier to write. For developers using conda, this is a
first step on a long path toward conda being directly importable. For conda users, this will
eventually result in more helpful and descriptive errors messages.
(2899, 2993, 3016, 3152, 3045)
* **Empty Environments**: Conda can now create "empty" environments when no initial packages
are specified, alleviating a common source of confusion. (3072, 3174)
* **Conda in Private Env**: Conda can now be configured to live within its own private
environment. While it's not yet default behavior, this represents a first step toward
separating the `root` environment into a "conda private" environment and a "user default"
environment. (3068)
* **Regex Version Specification**: Regular expressions are now valid version specifiers.
For example, `^1\.[5-8]\.1$|2.2`. (2933)
Deprecations/Breaking Changes
* remove conda init (2759)
* remove conda package and conda bundle (2760)
* deprecate conda-env repo; pull into conda proper (2950, 2952, 2954, 3157, 3163, 3170)
* force use of ruamel_yaml (2762)
* implement conda config --prepend; change behavior of --add to --append (3041)
* exit on link error instead of logging it (2639)
Improvements
* improve locking (2962, 2989, 3048, 3075)
* clean up requests usage for fetching packages (2755)
* remove excess output from conda --help (2872)
* remove os.remove in update_prefix (3006)
* better error behavior if conda is spec'd for a non-root environment (2956)
* scale back try_write function on unix (3076)
Bug Fixes
* remove psutil requirement, fixes annoying error message (3135, 3183)
* fix 3124 add threading lock to memoize (3134)
* fix a failure with multi-threaded repodata downloads (3078)
* fix windows file url (3139)
* address 2800, error with environment.yml and non-default channels (3164)
Non-User-Facing Changes
* project structure enhancement (2929, 3132, 3133, 3136)
* clean up channel handling with new channel model (3130, 3151)
* add Anaconda Cloud / Binstar auth handler (3142)
* remove dead code (2761, 2969)
* code refactoring and additional tests (3052, 3020)
* remove auxlib from project root (2931)
* vendor auxlib 0.0.40 (2932, 2943, 3131)
* vendor toolz 0.8.0 (2994)
* move progressbar to vendor directory (2951)
* fix conda.recipe for new quirks with conda-build (2959)
* move captured function to common module (3083)
* rename CHANGELOG to md (3087)