Cleaned up python tutorials and added dependency checks to all tutorials

Former-commit-id: 246017f041

python/tutorial/101_FileIO.py

@@ -1,15 +1,16 @@
-from __future__ import print_function
 import sys, os
 
 # Add the igl library to the modules search path
 sys.path.insert(0, os.getcwd() + "/../")
 import pyigl as igl
 
+from shared import TUTORIAL_SHARED_PATH
+
 
 # Load a mesh in OFF format
 V = igl.eigen.MatrixXd()
 F = igl.eigen.MatrixXi()
-igl.readOFF("../../tutorial/shared/cube.off", V, F)
+igl.readOFF(TUTORIAL_SHARED_PATH + "cube.off", V, F)
 
 # Print the vertices and faces matrices
 print("Vertices: \n", V, sep='')