Notes here are a consolidation of all changes between 1.21.14 and 2.0.0.

Enhancements:
-------------

* Increase placeholder path to 255 bytes (affects only Linux/Mac. Packages need to be rebuilt to support longer embedded paths) #877
* Configuration is local, passed via config argument.  No more global config.  #953
* Created Python API in conda_build/api.py #953
* Separate build folders per-build to allow parallelism #953
* Add locking to allow safe parallelism #953
* Add build flag to turn off separate build folders (--no-build-id) #953
* Much greater test coverage across all modules #953
* Add CONDA_BUILD_STATE variable that reflects RENDER, BUILD, or TEST state of build #1232
* Add support for HG_ variables in meta.yaml templates (for hg repos) #207 #1234
* Add source_files test argument in meta.yaml to copy files from source into test #1237
* add a numpy.distutils patch to jinja templating, so that fortran projects using numpy can also use jinja2 (thanks @bladwig1) #1252
* Ensure that the build environment is on PATH during all tooling and testing #1256
* Make failure due to pip requirements in meta.yaml clearer #1279
* Allow API to accept either paths to meta.yaml files or MetaData objects, for better compatibility #1281
* Implement tests to verify api stability #1283
* Add build/noarch to recipe metadata.  Use for truly platform independent packages - same folder in every install. #1285

Bug fixes:
----------

* Fix error converting linux to win packages due to python version mismatch #481
* Fix infinite loop that occurred with circular dependencies being built #953
* Improve test data structures to allow profiling with pytest-profiling #953
* Fix version sorting in pypi skeleton generator #1238
* improve backwards compatibility* prefix build and test envs with _, so that conda can be installed in them #1242
* fix bdist_conda; add smoke test for it to Travis #1243
* fix windows entry points (duplicate bad logic) #1246
* fix inspect entry point in embedded conda.recipe #1251
* create build environment before looking for VCS in it.  #1253
* fix a deadlock with recursive environment creation on encountering packages with short prefixes #1257
 with conda commands #1259
* only compile pyc files if python is in the build prefix # 1261
* remove exception catch-all in build CLI, to show actual errors more #1262
* specify full paths to activate scripts to avoid PATH conflicts with virtualenv #1266
* clean up remnants of pipbuild #1267
* remove pyc files from any source_files arguments to test in meta.yaml (avoid __file__ errors) #1272
* copy files and folders when breaking hardlinks (rather than renaming) to avoid cross-filesystem errors #1273
* add Scripts folder to prepended binary paths searched on Windows #1276
* update MACOSX_DEPLOYMENT_TARGET hard-coded value to 10.7 (better fix soon) #1278
* disallow backslashes in meta.yaml fields describing paths (e.g. always_include_files) #1280
* prevent GIT_* env vars from containing newlines #1282
* restore prefix-lengths inspect command (lost in merging) #1283

Restructuring:
--------------

* CLI scripts have been gutted and moved to conda_build/cli.  Content from them is in
  conda_build, in scripts without main_ prefix.  #953
* Skeleton generators have been broken out of main_skeleton.py, and consolidated into
  conda_build/skeletons.  The contents of this folder are examined at runtime for pluggability.  #953