Checkin some changes related to experiment automation and vnode feedback:

	* configure, configure.in: Add sensors/canaryd/feedbacklogs
	template.

	* db/libdb.pm.in, db/xmlconvert.in: Add "virt_user_environment"
	table that holds environment variable names and values.

	* event/lib/event.c: Allocate memory of the right size for
	event_notifications.

	* event/program-agent/GNUmakefile.in: Add version.c file and
	add install targets for the man page.

	* event/program-agent/program-agent.8: Man page describing the
	program-agent daemon.

	* event/program-agent/program-agent.c: Add a bunch of convenience
	features: let the user specify the working directory for commands;
	save output to separate files on every invocation of an agent; let
	the user specify a timeout for a command; make the set of
	environment variables sane and add vars given in the NS file in
	the opt array; a "status" file containing process information is
	written out when children are collected.  Internal changes: child
	processes are c...