changed images from defaultblrtsimage back to blrtsimage and the alternative images to altblrtimage...

Includes Mark Grondona's addition of the slurm_spank_local_user_init()
function, with my massaging to make it more compatible with the trunk code.
However, there is no support in the trunk API task launch code (and therefore
slaunch) for slurm_spank_local_user_init().  I will add that in a future
commit.

removed proctrack from jobacct since it won't allow us to keep track of tasks. (right now we may loose a child that reparents to init)

in order to free all memory (including that associated with pthread_create).

This avoid a segv, but more work is needed.