Add a ResourceStats protobuf message.
Extend profiling mode to have resource profiling.
Add funtions to operators to get resource stats
Collect CPU time in each LocalFragment if resource profiling is enabled.
Create the resource log table.
Build the whole pipeline of collecting, sending, recording and querying resource stats.
Add a REST API to get the last heartbeats of workers
SimpleAppender should also be a StreamingStateEncoding.
Just a small fix since it was neglected.
Set new operator ids for recovery tasks.
Also a fix that each fragment from the recovery task need to be called start().
Fix travis due to rebase to master