Merge pull request
#1398 from minrk/tb_syntaxerror...
Merge pull request
#1398 from minrk/tb_syntaxerror
fix %tb after SyntaxError
Moves exc_info extraction to Shell._get_exc_info, since it was done twice in different places, and differently.
Synchronizes expectations between showtraceback() and showsyntaxerror(), and ensures that sys.last_type, etc. get the right value.
Previously failing test added.
