commands that make use of the pointer position have an equivalent
command that operates solely on layout coordinates, or otherwise
avoids needing a pointer position. Added the command option
"down <instance>" to avoid using the pointer to disambiguate
selections. Added the command option "select ... at x y" to
do paint or cell selections at a specific coordinate instead of
the pointer position.
The website documentation now points to these contents in a clone
of the repository on opencircuitdesign.com, so all future edits of
the command-line documentation will be made directly to the git
repository. Also: Changed the precision of box values printed in
microns from 2 to 3 digits after the decimal place, so that 5 nanometer
grids do not get values clipped in the output.