428889 Don't include installMode="root" features in the product IU

- Ignore features marked with installMode="root" when publishing
  products. This attribute is currently only supported by Tycho (cf.
  bug 427563 for adding p2 support for this) and entails that the
  feature must *not* be referenced from the product IU. This is achieved
  with the changed implementation of getFeatures().
- This change allows to get rid of separate product file pre-processing
  steps in Tycho.

Bug: 428889
Change-Id: Ib7aa666c6746fbf417fa7437a7fa7b6a95ebd51f
8 files changed