Migrate to matrix-structs for event and response parsing

.ci/linux/gtest.sh

.ci/linux/run-tests.sh

.travis.yml

CMakeLists.txt

Makefile

include/ChatPage.h

include/MatrixClient.h

include/RoomState.h

include/Sync.h

include/TextInputWidget.h

include/events/AliasesEventContent.h

include/events/AvatarEventContent.h

include/events/CanonicalAliasEventContent.h

include/events/CreateEventContent.h

include/events/Event.h

include/events/HistoryVisibilityEventContent.h

include/events/JoinRulesEventContent.h

include/events/MemberEventContent.h

include/events/MessageEvent.h

include/events/MessageEventContent.h