elementary: rework Efl.Ui.Layout boolean signal-connection to Models

elementary: rework Efl.Ui.Layout boolean signal-connection to Models

Add new feature to specify signal connection to boolean properties of Models.
This also fix some '%v' substitution problems.

Parsing EINA_VALUE_TYPE_BOOL as boolean in Efl.Ui.Layout signal updates from
Models (instead of EINA_VALUE_TYPE_UCHAR). UCHAR no longer has special handling
and falls to the general result of eina_value_to_string() as other types do.

Use EINA_VALUE_TYPE_BOOL instead of EINA_VALUE_TYPE_UCHAR to signal selection on
click events to the Model.

Update examples to make usage of the new property connection feature in order to
model selection of items on Views.