2.0.0beta - 2016-06-05

Compatibility breaks:
---------------------------
* Increase placeholder path to 255 bytes (affects only Linux/Mac.  Packages need to be rebuilt to support longer embedded paths) #877

Bug fixes/Improvements:
-------------
* Respect proxy variables more appropriately #989
* Fix post-build variables when no build section existed in original meta.yaml #999
* Fix unix-style paths returned from git on Windows preventing relative paths from providing Jinja2 metadata #995
* improve logic handling "dirty" downloading.  Always download when not dirty.  #995
* Search packages on PyPI, rather than listing them all.  Should avoid some timeout errors there. #991
* Lightened requirement that x.x be defined in both build and runtime sections.  #650
* Search for single and double backslashes when finding files that need prefix replacement #962
* Fix missing encoding argument #987
* Don't use long prefixes on windows #985
* only set os.environ for non-None variables #981
* Track undefined jinja variables and use them to decide whether to download source #964
* handle patches with p0 or p1 #969

New stuff:
------------
* Add FEATURE_ environment variables for MKL, opt and debugging #978
* add new x86 and x86_64 selectors for Intel platforms #986
* add info/about.json file that contains the "about" section of meta.yaml #941
* Add msys2 paths to build and test environments #979
* allow ```--dirty``` flag to be passed to ```conda build``` command.  Skips download, and provides DIRTY environment variable in build scripts.  #973

Contributors:
-----------------
* @filmor
* @heather999
* @ilanschnell
* @jschueller
* @mingwandroid
* @msarahan
* @pelson
* @stuarteberg
* @whitequark