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

* Fix --source argument to build - was building when should only download source.  #1152
* Don't try to create work folder when it exists (but is empty) #1153
* Fix a logic error with need_source_download not existing #1148

New Things:
-----------

* Don't exit on compileall failure #1146
* Add CONDA_BUILD_RENDERING environment variable that is set during recipe rendering #1154
* Change pyc compilation to only affect files that would be packaged (not all of site-packages).  Compile pyc files on py3.  #1155
* Rename load_setuptools to load_setup_py_data (keep load_setuptools for compat; but show warning) #1156
* Test that condarc channels are respected in build #1157