some jobs may spawn child processes which change their process group
or session id, making the existing abort behavior of HUP-then-KILL to
the process group ineffective. Instead, if HUP to the process group
fails, recursively walk /proc and KILL anything with a ppid corresponding
to the leader process. This should keep working because the leader
process is a subreaper.
resolves#129
Implement a separate process, the "leader", which runs all the
scripts for a job run, instead of directly from the main laminard
process. This makes for a cleaner process tree view, where the
owning job for a given script is clear; also the leader process
acts as a subreaper to clean up any wayward descendent processes.
Resolves#78.
