Each take-in made a fresh set of source forms (newSourceForms), so each
read the whole mesh once to learn the forge's address: about 120 reads
at once at 16:08, each one more load on a store that was already full.
The take-ins of an inventory now share one reading, made again once it
is a minute old so a moved forge is read within that bound. A base that
could not be read is not kept. The forms' read takes a lock, since the
take-ins that share it run side by side.
Issues 1945 and 1277.
jschoubben
ef10a00f6d