Fixing issue #143 and 146- Cancel related bugs

Fixes https://github.com/azkaban/azkaban2/issues/143
If in queued state and a KILLED is called, there is a chance the flow would not continue.

Fixes https://github.com/azkaban/azkaban2/issues/146
If a flow is paused and a failure occurs, Cancel-all would not be respected until a resume.