Add method to atom to calculate Lewis acid/base vacancies
Add method to molecule to convert zero-order bonds to single or double bounds and adjust adjacent charges accordingly.
Add ZBO, ZCH, HYD extensions to MDL format
Stop AddHydrogens from resetting the ImplicitValencePerceived flag
Fix bug where unnecessary HYD values were written in MDL format
Remove leftover logging statements
Fix indentation
Merge remote-tracking branch 'upstream/master' into mdlextension
Merge pull request #18 from mcs07/mdlextension

MDL extension for zero-order bonds