Add 'unsymlink command to remove the symlink

setup.py

@@ -72,6 +72,7 @@ from setupbase import (
     install_symlinked,
     install_lib_symlink,
     install_scripts_for_symlink,
+    unsymlink,
 )
 from setupext import setupext
 
@@ -237,6 +238,7 @@ setup_args['cmdclass'] = {
     'symlink': install_symlinked,
     'install_lib_symlink': install_lib_symlink,
     'install_scripts_sym': install_scripts_for_symlink,
+    'unsymlink': unsymlink,
     'jsversion' : JavascriptVersion,
 }
 

setupbase.py

@@ -383,6 +383,15 @@ class install_lib_symlink(Command):
         print('symlinking %s -> %s' % (pkg, dest))
         os.symlink(pkg, dest)
 
+class unsymlink(install):
+    def run(self):
+        dest = os.path.join(self.install_lib, 'IPython')
+        if os.path.islink(dest):
+            print('removing symlink at %s' % dest)
+            os.unlink(dest)
+        else:
+            print('No symlink exists at %s' % dest)
+
 class install_symlinked(install):
     def run(self):
         if sys.platform == 'win32':