Version bumps

- Update project version to 1.0.2-SNAPSHOT, give that 1.0.1 is
    already released
  - Use _2.11 as the snapshot binary version for 2.12.0-SNAPSHOT
    PR validation.
  - Use 1.0.1 as the MiMa baseline
  - Use Scala 2.11.0 for Travis CI builds

Review by @gkossakowski