* New: In Hurricane, in Cell & Instance, add the ability to merge the
QuadTree when *second level* instances of a Cell are placed in
the same space as the top Cell. This is the case of a deeply
hierarchical design made of only standard cells that are to
be placed in a "flat" manner.
The design is uniquified then the intermediate instances models,
which should be unique at that point have their QuadTree merged
through a call to Instance::slaveAbutmentBox(). That method will
make the model of the instance use the QuadTree of the Cell to
which the instance belong. The instance model no longer posseses
a dedicated QuadTree. As a corollary the abutment box of both
Cell are kept identical and the Instance has it's transformation
set to (0,0,ID).
Remark: when we talk about "QuadTree", we mean in fact the
QuadTree for the instances *and* the SliceMap (Layer+QuadTree).
Consequence in Query: when going through the resulting
"flattened" QuadTree we will find objects with an incomplete
Path du to the fact that we didn't have to explore their
Instance/Cell level to reach them. The shunted part of the
Path is stored in the Go master Cell in the _shuntedPath
attribute. This also affect the displayed depth of hierarchy,
but not too badly.
* New: In Hurricane, in Cell, new methods:
- Cell::updatePlacedFlag() : set the placement flags.
- Cell::isUnique() : one or less instance.
- Cell::isUniquified() : is the result of an uniquification.
- Cell::isUniquifyMaster() : is the reference cell of the
uniquification.
* Change: In Hurricane, in Cell::Uniquify(), uniquify a Cell only
if it is unplaced. We do not need to duplicate placed Cells
(see datapathes).