update sbt plugins

* sbt-git (0.6.3 -> 0.6.4)
* sbteclipse (2.5.0-SNAPSHOT -> 2.5.0)
* findbugs4sbt (1.2.2 -> 1.3.0)
* cpd4sbt (1.1.4 -> 1.1.5)
* jacoco4sbt (2.1.4 -> 2.1.6)
* sbt-site (0.7.2-SNAPSHOT -> 0.8.1)
* sbt-pack (0.4.0 -> 0.6.2)