Create group_message_delivery.md
enable disabled bootstrap parallel tests
check possible duplicates from GetRandomPort
avoid segment fault (because of using non-const global variable in multi-threads)
catch up with the minor sqlite_wrapper API change
error handling (via re-attempts) is encapsulated in sqlite_wrapper, no need to carry out re-attempts on upper layer
Merge remote-tracking branch 'upstream/next' into next
Merge remote-tracking branch 'upstream/next' into next
Merge remote-tracking branch 'upstream/next' into next
Merge branch 'next' of github.com:Fraser999/MaidSafe-Routing into next
Merge remote-tracking branch 'upstream/next' into next
Merge remote-tracking branch 'upstream/next' into next
Merge pull request #20 from maqi/MAID-144_enable_disabled_tests

enable disabled bootstrap parallel tests
Merge remote-tracking branch 'upstream/next' into next
Merge pull request #29 from Fraser999/next

Added group message delivery doc.