Add sorting by number of nodes reserved (PCs column). Right now this
is total number, so it includes widearea nodes, but I plan to split
these apart. Sorting by PCs required changing in the initial query
quite a bit. Also changed the final report to include all classes, and
convert into a prettier table.
Add a minor optimization; instead of querying the DB for the number of
node classes used by experiment (which at this moment means 107
queries), do one query and split into a little hash table of per exper
usage totals.