Added Grouping unit test, extended Reduce integration test, added JavaDocs to ReduceFunction
Preliminary support for String arrays in new Java API
Improve error messages for instantiation errors on arrays and for programs without data sinks.
Add write mode to data set write function.
map operator test
flatMap operator test
Testcases for the CoGroup operator in the new Java API
Change return type of the CoGroup combine functions to a single value.
Add default empty method stub for combiners in CoGroup functions.
Add semantic property fields to single- and two-input udf operators.
Lots of comments.
Union implementation for new java api, with simple UnionIT testcase
Rewrite TypeExtractor to support more types and complex type structures. Possible Exceptions are now more user-friendly.
Fix of JVM 6 related bug and enhancement of 2 other corner cases.
Adjusted TypeExtractorTest for updates CoGroup combiner signatures.
Added comments and checks to the StringUtils
Added comments to the Tuple classes.
Add specialized type serializer for long[], including test.
Minor cleanups in Java API tests.
Minor cleanups in type extractor for new Java API.
Revert "Revert "revert type extractor stuff""

This reverts commit 13e68af5e5bc0105067704c07726be427ec5689b.
Merge branch 'master' into japi-python