Update dependencies and Maven plugins
Update dependencies and Maven plugins

Dependencies:
 - SLF4J-Log4j 1.7.12
 - JUnit 4.12

Maven plugins:
 - maven-compiler-plugin 3.6.0
 - maven-jar-plugin 3.0.2
 - maven-surefire-plugin 2.19.1
 - maven-dependency-plugin 2.10
 - maven-assembly-plugin 3.0.0
 - maven-release-plugin 2.5.3
 - maven-javadoc-plugin 2.10.4
 - maven-source-plugin 3.0.1
 - maven-gpg-plugin 1.6
 - buildnumber-maven-plugin 1.4

After updating the maven-assembly-plugin it is no longer necessary to
fix the versions of plexus-archiver and plexus-io used by the plugin.

hbz/metafacture-core,metafacture/metafacture-core,culturegraph/metafacture-runner,culturegraph/metafacture-core,metafacture/metafacture-core,cboehme/metafacture-core,hbz/metafacture-core,cboehme/metafacture-core,culturegraph/metafacture-core,culturegraph/metafacture-core,culturegraph/metafacture-runner,cboehme/metafacture-core,culturegraph/metafacture-runner,metafacture/metafacture-core,hbz/metafacture-core,cboehme/metafacture-core