Unresolved sbt dependencies

Compiling the tapasco sources with sbt compile leads to a build error due to unresolved dependencies.

Bug: sbt-assembly in version 0.14.4 cannot be resolved by sbt
Fix: update version in project/assembly.sbt to 0.14.6

Bug: sbt-scalastyle in version 0.8.0 cannot be resolved by sbt
Fix: update version in project/sbt-scalastyle.sbt to 1.0.0