Set -feature scalac options
Fix `-feature` warning about reflective access of structural type member value

Example warning:

    [warn] KafkaSpec.scala:98:
    reflective access of structural type member value messages should be enabled
    [warn] by making the implicit value scala.language.reflectiveCalls visible.
    [warn] This can be achieved by adding the import clause 'import scala.language.reflectiveCalls'
    [warn] or by setting the compiler option -language:reflectiveCalls.
Merge branch 'feature/enable-feature-flag' into develop
Use ScalaTest 2.1.6
Add change log