#154 Weaver optimization works for 50%

[Michiel Hendriks]

The weaver optimizes the places where it will weave hooks. This optimization checks for inputfilter and outputfilters to be present on a current class. But only in case of outputfilters will will skip the default output filter, this is not the case for input filters. So, the optimization for inputfilters never happens.

Should this optimization be done at all?