Pilotnet link fix

[bamsumit]

Issue Number: 22

Objective of pull request:
Fix broken link for Pilotnet

Pull request checklist

Your PR fulfills the following requirements:

• Issue created that explains the change and why it's needed
• Tests are part of the PR (for bug fixes / features)
• Docs reviewed and added / updated if needed (for bug fixes / features)
• PR conforms to Coding Conventions
• PR applys BSD 3-clause or LGPL2.1+ Licenses to all code files
• Lint (pyb) passes locally
• Build tests (pyb -E unit) or (python -m unittest) passes locally

Pull request type

Please check your PR type:

• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation changes
• Other (please describe):

What is the current behavior?

• The link is broken.

What is the new behavior?

• The link is fixed. Additional automated download script added.

Does this introduce a breaking change?

• Yes
• No

Supplemental information

[mgkwill]

Approving with the caveat that we should document that this only works on Linux with wget, unzip installed.