[Rev 01] RFR: Add Host::isMemberOf

[Erik Helin]

The pull request has been updated with additional changes.

----------------

Added commits:
 - 417b671f: Use String instead of long for groupId

Changes:
  - all: https://git.openjdk.java.net/skara/pull/173/files
  - new: https://git.openjdk.java.net/skara/pull/173/files/52633d26..417b671f

Webrevs:
 - full: https://webrevs.openjdk.java.net/skara/173/webrev.01
 - incr: https://webrevs.openjdk.java.net/skara/173/webrev.00-01

  Stats: 19 lines in 5 files changed: 12 ins; 0 del; 7 mod
  Patch: https://git.openjdk.java.net/skara/pull/173.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/173/head:pull/173

PR: https://git.openjdk.java.net/skara/pull/173