* Add context managers for writers
Allow calling close() on already closed Writers
Fixes#2217
* add a close method to MolSuppliers
* modernize the way we handle presence/absence of MAEPARSER support
* add context managers to suppliers
* changes in response to review
* some cleanup
* more cleanup
* auto generate coords in mol block writer if includeChirality = True
* default to include chirality when writing mol blocks/files
* make isomeric smiles the default; note that not all tests are passing at the moment
* update a reaction test
* update expected cartridge search results
at this point all python, c++, and cartridge tests pass
* docs
* update incompatibility docs
* update doctests
* these now build
* minor example update
* update expected c++
* typo
* make allowCXSMILES=true the default
* add auto perception of chirality when reading 3D structures from mol blocks
* explain changes in release notes
* further doc update
