Proper open/close handling of combine stubs in combining sorter.
Combine stubs are lazily initialized upon spilling.
Adjusted combining sorter test cases.
Updated contributors.
Added cobertura Maven plugin for test coverage report generation
Added JDBC Input Formant and tests.
Fixed serialization warnings.
Marked transient fields.
Minor formattings.
Adjusted JDBC example to use internal derby DB for better debugging support.
Added DefaultInputSplitAssigner as default fallback for GenericInputSplit.
Fixed handling of unsplittable inputs and added sanity checks.
Removed redundant split generation in JDBC format after fixing unsplittabel input behavior.
Merge JobManager Webinterface
FileInputFormat builder accepts GenericDataSources.
Extended UniformPactRecordGenerator to produce keys and values starting at an offset
Extended DataSinkTask to support union input and added corresponding test case and integration test.
Fix typo in serialization method name.
Add Pregelsphere
Executor services use daemon threads which prevents lingering threads at job end.
Make 'closed' status in hash join atomic to prevent multiple concurrent closing.
Added missing googleapi
Fix concurrent memory release in HashJoin cancel case.
Minor formattings.
Add "stratosphere-yarn" sub-project

based on https://github.com/hortonworks/simple-yarn-app

Build debian package only with special profile for that (to speed up the build)
Build uber-jar of stratosphere (for super-handy yarn deployment)

Old commit messages (from rebase:)

advanced configuration file handling (maven and jar magic)
Command line arguments for client (not yet done)

Change JobManager startup to allow external control
Use environment variables to pass variables to ApplicationMaster
Use contstants for settings
Fix CLI options
minor refinemens (pact-hbase dependencies)

Yarn runs with HDFS
jar files and configs are now shared using hdfs
many many deployment bug fixes
uberjar is automatically uploaded to dopa server