Added code for reflective avro types.
Introduced CREATE and OVERWRITE file output write modes. OVERWRITE is default (as before).
Rewrote code for file output path preparation.
Fixed distributed writing to local filesystem #286
Added test for write modes on local file system
Updated configuration keys to new naming
Added optional parameter to always write into directories even in case of DOP = 1.
Extended FileOutputFormatTest.
Some code beautifications.
Adapted KMeans example such that also points with assigned cluster IDs are written as result.
Adapted KMeans TestCases.
extend and expose KMeansDataGenerator
Fixed broken build
Added API for broadcast variables.
Added KMeans Java examples using the broadcast variables API.

Added KMeansIterativeBroadcast Java example.
Added KMeansSingleStepBroadcast Java exampe with integration test.