use start_ipython in entry points

increases visibility of the public API to snoopers.

IPython/scripts/ipython

@@ -2,6 +2,5 b''
 """Terminal-based IPython entry point.
 """
 
-from IPython.terminal.ipapp import launch_new_instance
-
-launch_new_instance()
+from IPython import start_ipython
+start_ipython()

setupbase.py

@@ -315,7 +315,7 b" def find_scripts(entry_points=False, suffix=''):"
     """
     if entry_points:
         console_scripts = [s % suffix for s in [
-            'ipython%s = IPython.terminal.ipapp:launch_new_instance',
+            'ipython%s = IPython:start_ipython',
             'pycolor%s = IPython.utils.PyColorize:main',
             'ipcontroller%s = IPython.parallel.apps.ipcontrollerapp:launch_new_instance',
             'ipengine%s = IPython.parallel.apps.ipengineapp:launch_new_instance',