Tycho build for org.eclipse.egit.ui.test

Tycho build for org.eclipse.egit.ui.test

Following approach described in [1].

Fixed dependencies:
- correcting wrong version range for org.eclipse.core.filesystem
- org.eclipse.ui and org.hamcrest need to be referenced via require-bundle

Make GitCloneWizardTest.canCloneARemoteRepo() independent from Eclipse
workspace name. This eliminates the need to configure the workspace used
by the test run from Tycho.

Introduce maven property "ui.test.vmargs" to enable passing VM parameters to the
VM running the tests.

Also introduce maven property "platform-version-name" to simplify building
against different Eclipse platform releases. E.g. to build and test
against helios platform release run

mvn -Dplatform-version-name=helios clean install

The following platform versions are supported:
- ganymede
- galileo
- helios

The tests are executed in the integration-test phase of the default Maven
lifecycle [2].

Since the feature org.eclipse.sdk.ide is not available in the ganymede p2
repository the feature org.eclipse.pde.feature.group is used to setup the
test harness.

[1] https://docs.sonatype.org/display/TYCHO/How+to+run+SWTBot+tests+with+Tycho
[2] http://maven.apache.org/guides/introduction/introduction-to-the-lifecycle.html

Change-Id: I06e94589589ad18b50daf641d89fd65a8c46f694
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>