BugFix: move event to the top of the list of creation

stream rates tries to add listener to drone event but drone event is
not created yet
Merge pull request #571 from azrin1972/BugFix--Exception-upon-startup

BugFix: move event to the top of the list of creation
Merge branch 'master' of https://github.com/jason4short/droidplanner into UI_Jason2