Adding failure path to data loading
fixing data locality bug
Merging master
Merge remote-tracking branch 'origin/master' into shravan_dataloading_failure
Tested failure in local mode

Have added submitting the data load conf as a service conf and the
required changes in the DataLoader. I have also 'poisoned' :) the
linecounter example with 40% failure rate and the code still manages to
complete with the correct result!
Some micor changes and a test case
refactor DataLoadingREEF example main class
minor refoprmatting of LineCounter example
Merge branch 'master' of github.com:Microsoft-CISL/REEF into sergiym_refactor_failing_dl
refactored LineCounter class in the DL example
refactored LineCountingTask; started refactoring DataLoader
refactored DataLoader and Utils
refactored InputFormatLoadingService and around
started Poisson poisoned driver (not finished yet)
use apache commons math3 to get Poisson RV (not tested yet)
more refactoring in FailureDriver and client/tests
refactored resource request handler for the data loader
minor refactoring of DataLoadingRequestBuilder
renamed some inner classes for DataLoader and FailureDriver;
DataLoadingRequestBuilder.build() can throw
mention issue #855 in the code