fix #350 (AQL normalization fails for node with two outgoing edge annotations)
update version to 3.1.8
updating changelog
add regression test for #350
Finish annis-3.1.8
Merge branch 'master' into develop

Conflicts:
	Misc/changelog.py
	annis-gui/pom.xml
	annis-interfaces/pom.xml
	annis-interfaces/src/main/java/annis/model/QueryNode.java
	annis-kickstarter/pom.xml
	annis-libgui/pom.xml
	annis-service/pom.xml
	annis-visualizers/pom.xml
	annis-widgets/pom.xml
	buildbot_scripts/copyService.sh
	doc/Doxyfile
	pom.xml