move pickleshare to external

can remove and make a dependency when pickleshare installs on 3.4 (should be 0.5)

IPython/external/pickleshare/__init__.py

@@ -0,0 +1,4 b''
+try:
+    from pickleshare import *
+except ImportError:
+    from ._pickleshare import *

IPython/core/interactiveshell.py

@@ -63,7 +63,7 b' from IPython.utils.decorators import undoc'
 from IPython.utils.io import ask_yes_no
 from IPython.utils.ipstruct import Struct
 from IPython.utils.path import get_home_dir, get_ipython_dir, get_py_filename, unquote_filename, ensure_dir_exists
-from IPython.utils.pickleshare import PickleShareDB
+from IPython.external.pickleshare import PickleShareDB
 from IPython.utils.process import system, getoutput
 from IPython.utils.py3compat import (builtin_mod, unicode_type, string_types,
                                      with_metaclass, iteritems)

IPython/external/pickleshare/_pickleshare.py

@@ -322,5 +322,3 b' def main():'
 
 if __name__== "__main__":
     main()
-
-