Updated MapsEngine.php

This change has been generated by a script that has detected changes in the
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Update README.md

Add a note about PHP 5.3.0 required for crypto.
Make config protected, remove services key

Tidy up config class re #266
Add extra error description to OAuth2 errors

Re #249
Merge pull request #320 from ianbarber/master

Fix two issues
Updated Genomics.php

This change has been generated by a script that has detected changes in the
discovery doc of the API.

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