Add avro input format for generic objects.
Add end to end test for avro with external jar and external test data.
Removed redundant object cloning in usercode wrapper to fix class loading issue.
Fixed logging in avro tets case
Serialization tags in ScalaInputFormat
Handle serialization / lazy initialization of UDF types in scala input formats
Fix bug in CsvInputFormat resulting from changing UserCodeWrapper

configure() is called twice on input formats because of statistics
generation. CsvInputFormat did not handle this gracefully.

Also change TPCHQuery3WithUnionITCase to TestBase2.
Added example program test jar
Simplified and fixed estimate computation.
Fix estimate computation and add (enable) additional tests.
Minor renaming of compiler hint
Adjusted file URIs in some tests for Windows compatibility
Made TextInputFormatTest platform agnostic.
Moved single-step kmeans program from examples to test project. Single step program is subsumed by iterative program.
Moved end-to-ent test from 'test' phase to 'verify' phase.
Updated some comments and minor example cleanup.
Operators use UDF class name as default name, when no other is specified.
Enabled plan visualization for broadcast variables (quick fix visualized broadcast inputs like regular inputs)
fix examples in GitHub readme page to 0.5 version usage
Cleaned up global sorting test cases and fixed latent bug in testing logic.
Fixed execution graph state checking to accept canceling -> failing transitions