Read initial value from the Hipadaba mdoel

Reading initial values from SICS can be slow, due to the fact that each value is read from a single transaction. This means it will take up to minutes to load value from the hipadaba model.

It is supposed that SICS will append all current value in the hipadaba model to initialise GumTree. This means GumTree only needs to monitor the changes in SICS to keep up-to-date.

The hipadaba model needs to be change to support this additional field (<value>xxx</value>).

The SICS monitor also need to be refactored to be initialised before loading the model, so no chance will be discarded during the model initialisation.