Changes to the History module. When an action is taken the history entry
will contain the ID of the project associated with that change, if
available (project associated with a task, file, forum, ...).
The History tab on the 'View Project' page will now show all actions taken
on objects associated with the selected project, instead of only actions
involving the project itself.
This is done through changes in the w2p_Core_BaseObject class and all its
descendants, whereas a variable to hold the project ID is initialized with
the name of the variable in the descendant object that contains that info,
and a new method (to be subclassed) returns a sensible description to the
history entry, instead of the current cryptic one.
This way each class (which knows best about the data it contains) is
responsible for creating the history entry descriptive text.