Various fixes. Notably, pssh needs to be run in interactive mode or it just hangs mysteriously while you beat your head against your keyboard trying to understand why.

tree.

Print the reserved_pid column, and considered nodes with a
reserved_pid to be non-free

I use the script all the time (I'm probably the only one), and was
tired of it not being very good for answerint the questions I wanted:
how many nodes are there in holding experiments, how long have they
been there, limiting to specific types, etc.

Add a bunch of command line options to limit to specific node types,
projects, etc. Also added the ability to display free nodes (somewhat
redundant with 'avail', I know), and sort by different columns
(such as the time the reservation started).

Default to only PCs - too much noise otherwise.

Print only useful columns from the database.

although the default is currently to do cooked mode in "basic" mode,
rather then "full" mode.

reboot the node; do not rely on tbswap figuring this out; too
fragile.