Manage enable/disable a row configuration in the parent model

[ejhernandez@…]

Some models such as RuleTable from trafficshaping module and every model which comprises firewall rules from firewall module seem interesting to enable/disable a rule in order not to remove them.

This will allow a user to set a high number of rules which may be disabled (not having effect) for some time. An attribute called enabled is added to every row if the model description includes enableProperty as true boolean.

[ejhernandez@…]

(In [8723]) Added enableProperty property in order to add enable field to the description setting as default value the one set by defaultEnabledValue closes #869 (spent 1)

[ejhernandez@…]

(In [8724]) Missing enabledRows method which returns only the enabled rows and fixing a bug on adding enabled field to the description prior caching field names and such refs #869 (spent 0.5)