The change fixes a crash when no filebase parameter is given for the filter.
The instance creation functions of these filters had spossible memory leaks in
case errors in the configuration occurred. In addition to these, they would be
successfully created even if unexpected parameters were given.
The tee, qlafilter, namedserverfilter and topfilter now support the same filter
options: case, ignorecase and extended. The extended filter option enables
the Extended Regular Expression syntax for the filters which is used when
matching queries.