Added expiration property.

Defaults to 60 minutes.
Update Readme.md

Fixed indentation.
Turn properties off and on per table
Revert "Turn properties off and on per table"

This reverts commit e16c1dd9f2a8f489c1a7c8534c04e601196b1bde.
expiresProperty default to false

Default is false to maintain backward compatibility.
Update Readme.md

Example code should match defaults.
Merge pull request #8 from ajostergaard/master

Added expiration property support courtesy of @ajostergaard