unserialize BlueObject (issue #22)

This version introduces multiple enhancements:

fixed error with double unserialize data

Details of additions/deletions below:
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Modified:   Base/BlueObject.php
            -- Updated --
                _appendSerialized removed duplicated `unserialize` function

Modified:   CHANGELOG.md
            -- Added --
                changelog information
Merge pull request #23 from chajr/fix

unserialize BlueObject (issue #22)