dummy estimator plugging into FlowStepStrategy
runnable MiniMRCluster test
implement basic 'inputSize/bytesPerReducer' estimator
test multi-step job in MiniMRCluster
minor changes/cleanup
make ReducerEstimator configurable by config variable
allow passing config to MiniMRCluster jobs, add needed Log4j class to path
rename/refactor/move
factor out common estimator code, handle override/explicit, save things in jobconf
move reducerEstimator creation into ExecutionContext via Config, update with things from Twitter internal version, pass Config to LocalCluster.initialize
de-dup a couple config params
format class list
add 'completedFlow' output on Job, use for 'inspectCompletedFlow' in HadoopPlatformTestJob
move 'HadoopNumReducers' into out into Config
changes from internal reviewboard

- prettier InputSizeReducerEstimator w/ foldLeft/match
- change some config parameter names
- throw ClassNotFoundException/InstantiationException
Merge branch 'develop' into bholt/estimator (had to move "buildFlow" addition)

Conflicts:
	scalding-core/src/main/scala/com/twitter/scalding/Execution.scala
remove unused loggers, use 'Option.collect' to get rid of compilation warning
add comment about 'completedFlow' var
refactor package name estimator -> reducer_estimation
return type of 'getReducerEstimator' should be more specific than 'FlowStepStrategy'