i created new class opal_proc_table_t which is based on opal_hash_table_t
and takes a key of type opal_process_name_t
internally, it uses two levels of opal_hash_table_t :
opal_proc_table_t->super = hash table for jobids
and in this hash table, there are opal_hash_table_t for all the vpids within the same jobid

this is currently used in opal/mca/dstore
and the next step is to use it in the btl

if we decide to have a separate hash table for the vpids of the local jobid,
then this implementation could be hidden in opal/class/opal_hash_table.c

i could only run minimal tests on this commit