* ARC_CONSTRUCTION_MANAGER: handles the logical flow of constructing an
arc by centre-point, set radius, set angle. This moves the logic out
of the Pcbnew DRAWING_TOOL event loop in drawArc().
* ARC_ASSISTANT: graphical overlay to communicate current arc shape to
the user during the drawing process
This simplifies the (already simple) SELECTION_AREA class. It is also
moved into KIGFX::PREVIEW and put in the common library, where it can be
reused by other GAL-aware tools (not just in Pcbnew) in future.
This introduces SIMPLE_OVERLAT_ITEM, which is an abstract EDA_ITEM,
designed for use as an overlay for assisting interactive tools.
The item is drawn only on the GP_OVERLAY layer, and sets the fill,
stroke and line properties before calling a virtual function to draw the
shape, which will depend on the implementaiton of the derived class.
The motivation here is to simplify and unify basic overlays used when
in interactive tools. It is not designed to be the base class of all
possible overlays - more complex ones would be more clearly represented
as their own derivative of EDA_ITEM.
Applications of this class can include: zoom/select rectangles, zone
polygon previews, geometric shape helpers, and so on.
More flexible node mapping in Spice netlist exporter
Allows to map nodes to pins for Spice models that have more pins than
corresponding schematic symbol. An example is a MOSFET model containing
gate, source, drain & body, whereas schematic symbol part has only gate,
source & drain with body and source connected inside the part.
Init'ing static wxBitmaps in the global scope happens before the GUI is
ready, which segfaults, at least on GTK+. This can happen in, for
example, the Python module. In normal use, the singletop/kicad
loader has initialised the GUI first, so it doesn't manifest there.
