* Add test for non abstract entities without icons
Fixes#575.
Test will now fail if an entity is added that is not abstract but has no icon.
Also added icons or made entities abstract that failed the test.
No non abstract entities actually missed textures.
Some notes: Changed name of "constructionghost" from "spooky ghost" to "construction ghost", and changed name of "AdminObserver" from "observer" to "admin observer" to avoid overlap in names.
* Split up client side and server side tests
