Fix validation errors for all target platforms

Fix validation errors for all target platforms

Main goal of this refactoring is to have newly created launch configs to
have zero errors on validation. With the below changes, I can run a
launch config with the setting "include all bundles of workspace and
target platform" without any validation error in all target versions.

* remove mylyn.sdk, because it includes unwanted dependencies to CDT and
mylyn.trac (differs by version)
* add some mylyn dependencies as bundles instead of features to avoid
the unwanted features
* add ecf dependencies in all targets (they existed only in 4.8)
* add eclipse.tools.layout.spy to all targets (where it exists) to
simplify debugging of SWT layouts
* replace 4.8-staging by 4.9-staging. this required fetching some mylyn
dependencies from the mylyn update site instead of the staging update
site, since they do not exist on the staging site

Change-Id: If06b976af162487cb25455e0fd52d2a26b831e2b
Signed-off-by: Michael Keppler <Michael.Keppler@gmx.de>
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>