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.

should do.

mode.

bad thing to do, and has recently stopped working. Use an index
ordering slot instead.

ProtoGeni's CM.

busy error.

Added GetNodeByVirtualId, GetLinkByVirtualId, and ReplaceNode as utility functions for managing rspecs.

Experiment: lets see if this helps revive stuck multicast sessions.
With "-K <seconds>", the client will send a IGMP-leave/IGMP-join after
<seconds> of no received packets.