Bug 399023 - Prepare Hudson build

There is no simple way to fetch from 2 git repositories in one Hudson
job. Hence enable a second build mode to enable splitting the build into
2 jobs on Hudson:
- first job to build the client bundles, resulting artifacts will be
  uploaded to Nexus
- second job to build the server, features, product and p2 repository
  and also perform static checks using findbugs and pmd. This job 
  consumes the client bundles from Nexus.

In order to build the server job call

mvn clean install -P platform-kepler,static-checks

To simplify local build of both client and server by default the
parameterless build of the server will also build the client bundles and
skip the static checks to reduce local build time. To build everything
in one local build run use the following command from the server's root
directory: 

mvn clean install
Bug 399023 - Enable running Orion server tests from Tycho

Use the build-helper-maven-plugin to reserve a free port for running the
Orion server tests from Tycho.

Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
Fix in orion.server parent pom
Minor test cleanup
Bug 407669 - Trying to save a deleted file pops up strange message
Fixed warnings and code cleanup