Peter M. Groen / openbr

Improvements to CompositeTransform::smartCopy

IgnoreBorder option for slidingWindow detectors

New transform to filter gallery based on meta-data

In stream, only release the calling thread after the last thread has exited
the last stage. This should prevent any issues related to the calling thread
being released, then deleting or otherwise damaging the stream while anything
is still active.

If we are doing nonsense like composing algorithms in memory, checking for
a NULL parent is not a viable way to detect when smartCopy has returned a
loose transform. This is because root transforms created through
algorithmCore or whatever also have NULL parents, but actually they will
be deleted via QSharedPointers, so adding them to a parent chain is
dangerous, and they can show up as child transforms if we say attach them
as children of a stream or distribute transform as part of a
parallelization scheme.

So, instead we add an output parameter to smartCopy indicating if the
returned pointer is a newly allocated transform, that is not already set
up to be deleted.