Revert dataframe example

It accesses all Iterations at once

Author: franzpoeschel

examples/11_particle_dataframe.py

@@ -35,11 +35,8 @@
 
 # This "if" is important for distributed dask runs
 if __name__ == "__main__":
-    s = io.Series("../samples/git-sample/data%T.h5", io.Access.read_only, {
-        "defer_iteration_parsing": True
-    })
-    # with defer_iteration_parsing, open() must be called explicitly
-    electrons = s.snapshots()[400].open().particles["electrons"]
+    s = io.Series("../samples/git-sample/data%T.h5", io.Access.read_only)
+    electrons = s.snapshots()[400].particles["electrons"]
 
     # all particles
     df = electrons.to_df()