New job state of warning and display a set of warnings about possible problems with a map reduce job.  Also, collect the number of records each map/reduce job and warn if a job does not write out any records
detect and store warnings via a callback from the lipstick ppnl
source presence of warnings directly from jobStats record rather than calculating them in the UI
fix rending of warnings
can't mock the JobStats class as it's made final so this is basically impossible to test
Warnings UI can be toggled on and off
if the jobstats say no records were written, double check against against counters as we've seen this return zero before for jobs that did write out records whose counters accurately reflected this.
detect reducer skew amounst each job's tasks
save job warnings as job is updated
was using the wrong warning key
include number of skewed reducers as well as the ids of those that are skewed
Put a floor for the threshold value so that one slightly slower reducer doesn't appear skewed if all the other reducers have a tightly coupled execution time.
update for changed attribute name
Include apache math library used for reducer skew detection
Handle the fact that an empty directory created on HDFS affects the bytes written counter, so if we want to use this counter to accurately warn when no records are written we must be able to detect empty directories. In passing fix order of operation bug that was causing completed job warnings to be over written by running job warnings resulting completed job warnings being lost
remove code artifacts that weren't meant to be included in pull request
disable warnings if running w/o a job tracker since the info we need in this case isn't available
example script which causes the m/r no output warning to be triggered
include warning message for skewed reducers
handle null values for constantexpressions