Parameter references

[kiith-sa]

Cross-referencing does not handle function and template parameters at the moment.

Parameters should be considered children of their function/class/template/whatever so e.g. methods of
a templated class can refer to its parameters. (As a side effect, e.g. a method will be able to to refer to other method's parameters like this: otherMethod.param)

Links to parameters should point to anchors in Params: lists, not separate files. This means we will
need to differentiate between child members and params in MembersTree (e.g. paramChildren instead of storing them all in children?) as well as when determining symbolLink by HTMLWriter.