Update README and examples with working Hash values

[tylerwalts]

With PR #79 responding to Oracle's change to the download site to add hashes to the URL, we now all have to be aware of the Oracle hash string (in addition to the build numbers).

This task is to:

• Update README overview with the reason why
• Update code examples to include hash values
• Ensure the hash values are actual values that work, from Oracle site.
  • Start with latest stable versions

Notes:

• This will change over time, every time Oracle makes a release.
• Nothing guarantees that Oracle won't re-publish all the artifacts again with some different hashes in the future.