* add AtomValenceException
* refactor a bit and add KekulizeException
* add copy ctor and copy() method
* add detectChemistryProblems
* add getType() method
want to be able to get the type of the exception without requiring doing a bunch of dynamic casts
* first pass at exception inheritance/translation
needs some cleanup and expansion, but this does pass all tests.
* cleanup and finish the python wrappers for the new exceptions
* make sure things are truly polymorphic
* wrap shared_ptrs of the new exception types
* expose DetectChemistryProblems()
* get the java wrappers building again
* transfer those changes to the c# wrapper
* add detectChemistryProblems()
and deal with the fun fun exception inheritance things that ensue
* response to review
