add QueuingMessageBus and use it to capture AddStatusIcon startup messages, fixing #2210
add QueuingMessageBus to capture AddStatusIcon at startup, fixing
prevent decommissioned icon on all buildings after reload
Merge branch 'master' of github.com:/dulrich/unknown-horizons
Merge remote-tracking branch 'upstream/master'
New test for clear and queue_len methods of QueuingMessageBus
Create QueingMessage subclass to use QueuingMessageBus with extra methods
fix selection test
apply the same deletion fix to build test
have tutorial test build enough houses to hit population target
split message busses into separate files and update imports
Merge pull request #2296 from dulrich/master

resolution for missing/wrong status icons at startup (issue #2210)