Fixing two minor bugs.

* ipapi now returns an InteractiveShell.
* Fixes a problem in ultratb so that %debug now works.

IPython/core/ipapi.py

@@ -25,6 +25,6 b' has been made into a component, this module will be sent to deathrow.'
 
 def get():
     """Get the global InteractiveShell instance."""
-    from IPython.frontend.terminal.interactiveshell import TerminalInteractiveShell
-    return TerminalInteractiveShell.instance()
+    from IPython.core.interactiveshell import InteractiveShell
+    return InteractiveShell.instance()
 

IPython/core/ultratb.py

@@ -902,7 +902,7 b' class VerboseTB(TBTools):'
                     self.color_scheme_table.active_scheme_name)
             # the system displayhook may have changed, restore the original
             # for pdb
-            display_trap = DisplayTrap(None, sys.__displayhook__)
+            display_trap = DisplayTrap(hook=sys.__displayhook__)
             with display_trap:
                 self.pdb.reset()
                 # Find the right frame so we don't pop up inside ipython itself