implement support for __prepare__ declarative method.  this signals that the mapping should not be constructed immediately; instead, the info for the mapping is placed into an interm object _MapperThingy which serves as the mapper for the purposes of figuring out inheritance, etc.  Later, the prepare_deferred_mapping() function can be called given a base which will invoke __prepare__ for each mapped class.
implement support for __prepare__ declarative method.  this signals that
the mapping should not be constructed immediately; instead, the info for
the mapping is placed into an interm object _MapperThingy which serves
as the mapper for the purposes of figuring out inheritance, etc.  Later,
the prepare_deferred_mapping() function can be called given a base which
will invoke __prepare__ for each mapped class.

WinterNis/sqlalchemy,alex/sqlalchemy,robin900/sqlalchemy,276361270/sqlalchemy,pdufour/sqlalchemy,Akrog/sqlalchemy,brianv0/sqlalchemy,j5int/sqlalchemy,EvaSDK/sqlalchemy,itkovian/sqlalchemy,Cito/sqlalchemy,alex/sqlalchemy,olemis/sqlalchemy,sandan/sqlalchemy,Akrog/sqlalchemy,davidfraser/sqlalchemy,bdupharm/sqlalchemy,sandan/sqlalchemy,graingert/sqlalchemy,dstufft/sqlalchemy,EvaSDK/sqlalchemy,Cito/sqlalchemy,inspirehep/sqlalchemy,alex/sqlalchemy,monetate/sqlalchemy,davidjb/sqlalchemy,epa/sqlalchemy,monetate/sqlalchemy,WinterNis/sqlalchemy,olemis/sqlalchemy,j5int/sqlalchemy,halfcrazy/sqlalchemy,ThiefMaster/sqlalchemy,dstufft/sqlalchemy,elelianghh/sqlalchemy,Cito/sqlalchemy,inspirehep/sqlalchemy,hsum/sqlalchemy,pdufour/sqlalchemy,wujuguang/sqlalchemy,davidjb/sqlalchemy,itkovian/sqlalchemy,wfxiang08/sqlalchemy,epa/sqlalchemy,robin900/sqlalchemy,bdupharm/sqlalchemy,ThiefMaster/sqlalchemy,sqlalchemy/sqlalchemy,elelianghh/sqlalchemy,graingert/sqlalchemy,bootandy/sqlalchemy,bootandy/sqlalchemy,brianv0/sqlalchemy,halfcrazy/sqlalchemy,wujuguang/sqlalchemy,276361270/sqlalchemy,wfxiang08/sqlalchemy,davidfraser/sqlalchemy,hsum/sqlalchemy,zzzeek/sqlalchemy