Some work on TautomerEnumerator (#3327)

* - Added a TautomerEnumerator constructor which allows passing CleanupParameters
- Added three configurable parameters to CleanupParameters
- Added a callback to TautomerEnumerator
- Fixed a bug where the same tautomer could be mapped by both isomeric and non-isomeric SMILES
- TautomerEnumerator::enumerate() now returns a TautomerEnumeratorResult and does not take
  dynamic_bitset pointers as optional parameters
- Added a missing transform from the Sitzmann paper
- General code cleanup and optimization

* - TautomerEnumeratorResult is now iterable in both C++ and Python
- further optimizations
- implemented a TautomerEnumerator.PickCanonical() Python wrapper
- added C++ and Python accessors to SMILES and SmilesTautomerMap

* - make sure the number of tautomers reported by rdLogger is correct and definitive

* make sure that if N maxTautomers are requested, N tautomers are returned if the theoretical number of tautomers is M>N

* avoid that sulfonic acids hit the formamidinesulfinic acid tautomerisation rule

* offer an option to allow the old API to still be used.

* Changes in response to review and following discussion with Gareth and Greg

* - made TautomerEnumeratorResult an enum class (was a plain C enum)
- made TautomerEnumeratorResult::const_iterator a bidirectional_iterator
- added tests to fully probe the TautomerEnumeratorResult::const_iterator functionality

* - change the difference_type definition
- added tests for the above

* - cosmetic change to improve code readability

Co-authored-by: greg landrum <greg.landrum@gmail.com>

Data/MolStandardize/tautomerTransforms.in

@@ -29,8 +29,8 @@ oxim/nitroso via phenol f	[O!H0]-[N]=[C]-[C]=[C]-[C]=[OH0]
 oxim/nitroso via phenol r	[O!H0]-[c]=[c]-[c]=[c]-[N]=[OH0]
 cyano/iso-cyanic acid f	[O!H0]-[C]#[N]	==
 cyano/iso-cyanic acid r	[N!H0]=[C]=[O]	#-
-//formamidinesulfinic acid f	[O,N;!H0]-[C]=[S,Se,Te]=[O]	=-- // TODO: WAT!?
-//formamidinesulfinic acid r	[O!H0]-[S,Se,Te]-[C]=[O,N]	=--
+formamidinesulfinic acid f	[O,N;!H0]-[C]=[S,Se,Te;v6]=[O]	=--
+formamidinesulfinic acid r	[O!H0]-[S,Se,Te;v4]-[C]=[O,N]	==-
 isocyanide f	[C-0!H0]#[N+0]	#	-+
 isocyanide r	[N+!H0]#[C-]	#	-+
 phosphonic acid f	[OH]-[PH0]	=