Merge branch 'master' into snap

Conflicts:
	README.txt
	plugin/src/main/java/hudson/plugins/virtualbox/VirtualBoxControlV40.java
	plugin/src/main/java/hudson/plugins/virtualbox/VirtualBoxControlV41.java
Merge remote-tracking branch 'parent/snap'

Conflicts:
	README.txt
	plugin/src/main/java/hudson/plugins/virtualbox/VirtualBoxControlV40.java
	plugin/src/main/java/hudson/plugins/virtualbox/VirtualBoxControlV41.java