Both now use through a common JsonConverter<> template class with its
base definition tuned for structs/QJsonObjects and specialisations for
non-object types. This new implementation doesn't work with virtual
fillJson functions yet (so EventContent classes still use toJson as a
member function) and does not cope quite well with non-constructible
objects (you have to specialise JsonConverter<> rather than, more
intuitively, JsonObjectConverter<>), but overall is more streamlined
compared to the previous implementation. It also fixes one important
issue that pushed for a rewrite: the previous implementation was not
working with structure hierarchies at all so (in particular) the Filter
part of CS API was totally disfunctional.

This should cover the Connection-related part of #253.

Connection gained lazyLoading/setLazyLoading accessors and the respective Q_PROPERTY.
When lazy loading is on, sync() adds lazy_load_members: true to its filter.

The members of the summary can be omitted in the payload; this change fixes calculation
of the roomname from hero names passed in room summary. Also: RoomSummary can be dumped to QDebug now.

…ndefined

Commit fd52459 introduced a regression rendering the cache unusable
after a client restart (an empty state overwrites whatever state was in
the cache). This commit contains the fix, along with more room change
tracking.

This concludes beta-version of lazy-loading support in libQMatrixClient (#253).

...instead of the entire function body wrapped in an if block.

GetMembersByRoomJob was dysfunctional so far, creating "unknown
RoomMemberEvents" instead of proper ones. Now that we need it for lazy-
loading, it's fixed!

Closes #253.

Case in point: matrix-org/matrix-spec-proposals#1750

… is done

Because lazy-loading test is executed on a room different from the test room.