Fix reaction display

CMakeLists.txt

resources/qml/Reactions.qml

src/Cache.cpp

src/Cache_p.h

src/timeline/EventStore.cpp

src/timeline/EventStore.h

src/timeline/Reaction.cpp

src/timeline/Reaction.h

src/timeline/ReactionsModel.cpp

src/timeline/ReactionsModel.h

src/timeline/TimelineModel.cpp

src/timeline/TimelineModel.h