and merged the contents into drcmgr.tcl, with a new button in the
DRC manager for saving the DRC contents. Loading is somewhat less
useful since the DRC error tiles are interactive. The DRC manager
still has the issue that every checked edge becomes a separate
entry; this is an artifact of the way the DRC checker works, but
it creates large numbers of error areas, many of which are redundant.
categorized by error type and scrolled through conveniently. However,
it needs work dealing with finding the actual error bounds. The
"DRC count" counts tiles, which is tile-plane-geometry-specific, and
"DRC listall why" fractures errors both over tiles and over the square
areas that the interactive DRC splits the layout into, for performance.
The DRC error plane needs to be changed to hold different types for
each error class, so that errors can be scanned by boundary instead of
by tile (work to be done).