Remove discouraged access warnings from github bundles

Remove discouraged access warnings from github bundles

Both the egit.github.* and mylyn.github.* bundles are managed by the
Eclipse EGit project. It seems reasonable to allow x-friend
access to egit internal packages in the same manner that other egit
bundles allow this, since incompatible changes will immediately lead to
compile errors.

The change only adds x-friends for actually existing discouraged access
warnings from *.github.* to *.egit.* (somewhat more than 100 warnings,
that are now gone). It does not fix any other discouraged access to
platform or mylyn.core.

Change-Id: Ib14c1a96b5f60bb354cd04e1fe3d23aae897ce6d
Signed-off-by: Michael Keppler <Michael.Keppler@gmx.de>
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>