* 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
* add overrides for what()
* translation fot KeyErrorException; update tests
* Switch all exceptions to `const char *` as a return type from message() (#4)
* switch return type of message() from std::string to const char *
* adjust one test to the new return type from message()
remove unnecessary verbosity from some tests
* fix cartridge build: update call to message().c_str()
* rebase agains master; fix another issue in cartridge build
* add deprecation note for message() and getMessage()
* amend Release notes
Co-authored-by: Greg Landrum <greg.landrum@gmail.com>
