Added a new Lua library name to try loading with dlopen() in Lua
based plugins.

This allows scripted modification of job records, by exposing the
 * job_ptr->direct_set_prio
 * job_ptr->priority
 * job_ptr->details->nice
fields to the job_submit.lua script.

#include <slurm/slurm.h>
to 
#include "slurm/slurm.h"
so that the original source gets searched first

    job_submit and job_modify functions as an error and the user request should
    be treated as an error.

Add submit_uid to the job_submit function calls. add partition access filtering to the job_submit/lua plugin
(e.g. don't pass info about partition that this user can't access).

 have lua module reference C code to get/set job fields