Use all task/event fields in SFDC activity-related triggers and filters

When using the "activity is logged", "activity is updated" triggers and the "activity was logged" and "activity was updated" filters, we need to be able to leverage all SFDC activity standard and custom fields.

We also need better precision on what field is updated (typically status), with the notions of old value / new value to be used as contrains.

These are needed as we are developing Account Based Marketing techniques that require betted collaboration with sales.

-Greg