Merge branch 'release-0.3.0' into develop
Merge branch 'hotfix-0.3.1' into develop
add events and event handlers
add event dispatcher (in the manager)
add documentation for event functions and classes
remove events from the roadmap
Merge branch 'feature-events' into develop
change the way entities are stored (now in a map with component types)
fix the tests when finding the entity
improve the examples
remove the archetype function, it is useless with the new subscribe
remove Archetype.cc from CMakeLists.txt (oups)
Merge branch 'feature-easy-subscribe' into develop
useless forward declaration (class does not exist anymore)
change the type of EventHandler to std::function (more generic)
change the call to ApplyLinearImpulse for Box2D 2.3.0
Merge branch 'feature-std-function' into develop
bump version to 0.4.0
Merge branch 'release-0.4.0'