in function shmdb_initParent add the param option to control the level of log
update document
Merge commit '3b813df6f16bc3e57fdb0ec373bb60287ad1e0f3'
remove some unused code.
destory the shared memory atfer ShmdbObject is reclaimed by v8.
Squashed 'extenal/shmdb/' changes from 3b813df..7ed89a6

7ed89a6 remove some unused code.
e179337 Merge commit '3b813df6f16bc3e57fdb0ec373bb60287ad1e0f3'
3f55426 update document
ab8ae9d in function shmdb_initParent add the param option to control the level of log

git-subtree-dir: extenal/shmdb
git-subtree-split: 7ed89a6283f8e5ce8c1e1b9f4c0fbdb7c743e747
Conflicts:
	extenal/shmdb/src/mm.c
Conflicts:
	extenal/shmdb/src/mm.c