* 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
* first cleanup
* next round of changes. all tests pass
* Fixes#2909
* Fixes#2910
* further cleanup
* some cleanup/refactoring of the Dict class
* remove now extraneous calls to hasProp() before clearProp()
* minor refactoring of RDProps.h
* Switch from using our own version of round() to std::round()
* replace some boost::math stuff with the equivalents from std::
* cleanups in SmartsWrite
* refactor out a bunch of duplicated code
* fix an instance of undefined behavior
* changes in response to review
* run clang-tidy with readability-braces-around-statements
clang-format the results
clean up all the parts that clang-tidy-8 broke
* fix problem on windows
