Cleaned up python tutorials and added dependency checks to all tutorials

Former-commit-id: 246017f041

python/tutorial/102_DrawMesh_TCP.py

@@ -1,11 +1,15 @@
-## This is a test application for the TCPViewer
-
-# Add the igl library to the modules search path
 import sys, os
-sys.path.insert(0, os.getcwd() + "/../")
-
-import os
 import time
+# Add the igl library to the modules search path
+sys.path.insert(0, os.getcwd() + "/../")
+import pyigl as igl
+
+import tcpviewer
+
+from shared import TUTORIAL_SHARED_PATH
+
+
+## This is a test application for the TCPViewer
 
 # Launch the tcp viewer
 os.system("python ../tcpviewer.py&")
@@ -13,13 +17,10 @@ os.system("python ../tcpviewer.py&")
 # Wait for it to set up the socket
 time.sleep(1)
 
-import pyigl as igl
-import tcpviewer
-
 # Read a mesh
 V = igl.eigen.MatrixXd()
 F = igl.eigen.MatrixXi()
-igl.readOFF('../../tutorial/shared/beetle.off', V, F)
+igl.readOFF(TUTORIAL_SHARED_PATH + "beetle.off", V, F)
 
 # Send it to the viewer
 viewer = tcpviewer.TCPViewer()