Maven now tests if files generated by the archetypes do actually build
[FLINK-1042] Changed ClassLoader field to be transient.

Serialization of the `RuntimeStatefulSerializerFactory` fails because the field `ClassLoader loader` is not serializable. The fix makes the field `transient`.

Author: Fabian Hueske <fhueske@apache.org>

Closes #92 from fhueske/StatefulSerializerFactoryFix and squashes the following commits:

c01cc27 [Fabian Hueske] [FLINK-1042] Changed ClassLoader field to be transient.
Remove field0 from CoGroup and Join Operator

These were added before to force the user to specify at least one key
field. Now, the user is also forced to specify at least one key because
otherwise the call would be ambiguous because of tuple key fields and
expression keys.
Change python2.7 to python in KMeans Quickstart
[FLINK-966] java examples included in packaged example directory

This closes #90
Fix problems with missing files/dependencies with cdh-4 distribution.
Fix legacy names in static webclient contents
Fixes on CDH4 build / Maven improvements:
- remove usages of commons-lang (we use only commons-lang3, as defined in flink-runtime/pom.xml)
- Upgrade maven failsafe to 2.17 so that tests also fail if the test errors (exceptions during execution)
- added new build profile "docs-and-source" that creates javadocs and source attachments. These are usually only needed when releasing (--> speed up the build)
[FLINK-1046] Made sure that Client uses correct user-code class loaders.
Add Sanity Checks for Join/CoGroup with SolutionSet in Record API

We now check whether the key fields specified for the delta iterations
match those specified when joining/coGrouping with the solution set.
This code is more or less copied from the new Java API.

The Scala API uses the Record API underneath so it is also covered.
[FLINK-1047] Fixes main class for start-local.bat
[FLINK-1048] Swallow output of SET statements in ./bin/flink.bat
[FLINK-1051] ./bin/start-local.bat prints error message if java.exe cannot be found
Another fix for CDH4 compliance
Adjusted examples packaging to only create jars for fully self-contained examples.
[FLINK-1053] Add "mapPartition" operator.
[FLINK-1053] Cleanup implementation of mapPartition function

This closes #42
Small bug fixes for running hadoop output formats

This closes #75
[FLINK-1054] Fix job history view in web frontend
[FLINK-1006] Added support for the MapR file system