ipython_directive, report except/warn in block and add :okexcept: :okwarning: options to suppress
PEP8 fix
Guard against self.state is None
Remove explicit passing state arg in favor of self.directive.state
Document previous fix re cython magic support in ipython_directive
add additional clarification in ip_d re prompt stripping
Document :okexcept:, :okwarning: in file header
Merge pull request #4870 from y-p/PR_ipython_directive

ipython_directive, report except/warn in block and add :okexcept: :okwarning: options to suppress