Rework Poly example on pydpf (#798)

* Create test codes for big files and work on poly example

* Tests On big Files

* Rework poly example

* Correction on poly example

* Rework poly example

* Rework the poly example

* THE FINAL Poly example

* Implements comments

* Implements comments

* Implements comments

* Implements comments

* Implement comments

Author: MichaelNale