Added dependencies: pickleshare and PyX

setup.py

@@ -495,9 +495,18 @@ def add(self, source_file, dependency_mod_time=0.0):
 
 ext_modules = [SnapPyC, SnapPyHP, TwisterCore]
 
-install_requires = ['plink>=2.4.2', 'spherogram>=2.2', 'FXrays>=1.3',
-                    'snappy_manifolds>=1.2.1', 'low_index>=1.2',
-                    'pypng', 'decorator', 'packaging', 'tkinter-gl>=1.0a3']
+install_requires = ['FXrays>=1.3',
+                    'plink>=2.4.2',
+                    'spherogram>=2.2',
+                    'snappy_manifolds>=1.2.1',
+                    'low_index>=1.2',
+                    'tkinter-gl>=1.0a3',
+                    'decorator',
+                    'packaging',
+                    'pypng', # Used to save OpenGL images.
+                    'PyX', # Used to save PDF images of links.
+                    'pickleshare', # To avoid https://github.com/ipython/ipython/issues/14416
+                    ]
 try:
     import sage
 except ImportError: