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)