method naming changes & data preparation (issue #25, #21)

This version introduces multiple enhancements:

changed some methods name to remove prefixes used for magic methods
added new magic method `restore` to restore data for given key
added some features to handle data set and get preparation
refactored some methods to manage class array variables

Details of additions/deletions below:
--------------------------------------------------------------

Modified:   examples/base_object/data_validation.php
            -- Updated --
                method naming

Modified:   examples/base_object/replace_data.php
            -- Updated --
                method naming

Modified:   Base/BlueObject.php
            -- Added --
                $_dataPreparationCallbacks list of callbacks to prepare data before insert into object
                $_dataRetrieveCallbacks list of callbacks to prepare data before return from object
                _genericPut
                _genericDestroy
                _genericReturn
                _getCorrectList return name of data list variable for given data type
                putPreparationCallback
                destroyPreparationCallback
                returnPreparationCallback
                putReturnCallback
                destroyReturnCallback
                returnReturnCallback
            -- Updated --
                __call added restore magic method
                hasErrors renamed to checkErrors
                getObjectError renamed to returnObjectError and logic moved to _genericReturn method
                clearObjectError renamed to removeObjectError and logic moved to _genericDestroy method
                getOriginalData renamed to returnOriginalData
                hasDataChanged renamed to dataChanged
                keyDataChanged used method rename
                putValidationRule logic moved to _genericPut
                destroyValidationRule moved to _genericDestroy
                returnValidationRule moved to _genericReturn