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

* Speed up package inspection by optimizing package file lookup  #2535
* Simplify hashing scheme.  A hash will be added if all of these are true for any dependency:

  * package is an explicit dependency in build, host, or run deps
  * package has a matching entry in conda_build_config.yaml which is a pin to a specific version, not a lower bound
  * that package is not ignored by ignore_version

  OR

  * package uses ``{{ compiler() }}`` jinja2 function

  All other packages will no longer have hashes. The takeaway message is that
  hashes will appear when binary compatibility matters, but not when it doesn't.  #2537

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

* Allow packages to store files in info folder  #2538
* Fix source_files not working correctly when using test files in packages  #2539