* Nonchiral atoms should be removed from StereoGroups
This fixes a bug where atoms which have no chirality were left in StereoGroups
In order to make this work, ROMol::setStereoGroups() needed to be made public.
That shouldn't be a problem since it doesn't change connectivity.
* support CXSmiles extensions in the hashes
* initial tests for that
* some cleanup
* copyright header cleanup
* minor refactoring
* call out the changes in the release notes
* extension and more testing
* add python wrappers
* Deprecation: planned removal of .message() and .getMessage() methods
* Deprecation: planned removal of old MolHash code
* document deprecations
* output the diffs when the psql tests fail
* remove .message() from SWIG wrappers
note that the KeyError doesn't work properly. We should clean up the the exceptions here anyway
* typo
* copy in, get building, add some basic tests
* complete the testing
Except for regiosiomers, which do not work
* regioisomers work now
* backup commit; things work
* remove last of NM macros from hashfunctions.cpp
* remove last of NM macros from hashfunctions.cpp
* remove dependency on the abstraction layer
* typo
* start using namespaces
clang-format
* switch to using enums for the HashFunctions and StripTypes
* Add initial python wrapper (and tests)
* move the new hashing code to the MolHash library
still may want to revise the naming of this
* Setup deprecation of the older hashing code
* better release notes text
* change in response to review
