Enhance samepath function with existence check

Add check for path existence before comparing.

Author: scivision

+stdlib/+python/samepath.m

@@ -1,5 +1,10 @@
 function y = samepath(path1, path2)
 
+if ~stdlib.exists(path1) || ~stdlib.exists(path2)
+  y = false;
+  return
+end
+  
 try
   y = py.os.path.samefile(path1, path2);
 catch e