put this_node_id_ into the mutex lock
use shared_ptr to wrap COW string avoid data racing
NodeId forced copy (avoiding raw_id_ becoming invalid after movable constructor being called)
avoid the situation when empty connection_ptr is returned
capture by value
Merge pull request #51 from maqi/MAID-545_LNC_thread_sanitizer

Maid-545_LNC_thread_sanitizer
Merge branch 'next' into account_transfer
Merge branch 'next' into account_transfer
Merge branch 'next' of https://github.com/maidsafe/MaidSafe-RUDP into next