Some fixes on reflection tests (firebird):
Some fixes on reflection tests (firebird):

 * firebird doesn't support create table tablename (columnname type NULL)" syntax (only NOT NULL)
 * firebird doesn't support schemas

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