Named filters

The Filterable interface supports the definition of muliple filter definitions in parallel.

A filter may be defined setFilter("myId", myFilter).
The filter may be reset by calling setFilter("myId", null).

For PmTableImpl there is a specific filter semantic:

• Filters defined by calling setFilter() will be removed whenever a initialized PmEvent gets fired.
• Filters defined by calling setFixFilter() will never be removed automatically.