nitdoc: Insert some functions in MClass
nitdoc: Insert some functions in MClass

Adding directly in MClass functions to display the parents of a class,
the subclasses and in which module it is redefined

Signed-off-by: Stefan Lage <cb0c5092503e2445cab1e9be9ee79fa90f718028@gmail.com>

StefanLage/nit,StefanLage/nit,StefanLage/nit,StefanLage/nit,StefanLage/nit