Redmine#3731: add promiser_pid and promiser_ppid
Redmine#3819: move promiser_*id to context initialization, outside the tight inner loop
Merge pull request #1171 from tzz/feature/3731-promiser-pid-ppid

Redmine#3731: add promiser_pid and promiser_ppid; Redmine#3819: move get* calls out of tight loop.