If the loaded events didn't contain any messages, the user will feel
like nothing loaded. Let's repeat the action until there is at least
one message is loaded

These strings were written for XMPP chats. Let's
avoid them for matrix chat

We shall use this in the future

We were not updating thread members and the members list were thus
almost always empty (Went unnoticed as we are not using thread members,
but shall be useful for matrix and SMS threads in the future)

This is a generic notifications that doesn't use any Purple
APIs, so that this can be used with other providers (like matrix).

Only the features used in chatty-notify.c is implemented here.
chatty-notify.c was used only to show message notifications,
and so the rest are not included.

The notifications are also shown after some delay, and multiple
message notifications are squashed into one when they are
received within a short timespan (currently 300 milliseconds)

Fixes #389

So that ui tests won't be run when building packages as those
tests require Xserver

Otherwise we are dereferencing a NULL value

Likely Fixes #415

So that we can debug better

Send messages serially so that we won't send too much
server requests the same time.  Also, recover if sending
message fails when it was sent too soon.

So that the cached room names are upto date in database.

And load them from db when chat history is loaded.

We were using the 'id' of the matching message time and load
the messages before that. This may fail if the messages
preceding that where loaded after (which will than have
a higher 'id')

So use time alone and load items before the given time.

If message is empty it's possible that the 'msg' variable
is never set, and thus pointing to an invalid memory as no
initial value was set.

So intialize the variable with NULL

The default per host connection limit is 2. Since `/sync` API is a blocking
one, we have just 1 another connection for use, for which the request can
be delayed if there is already a pending request.

So increase the limit to 6 (which is a lower common value used by many browsers)

These strings are escaped when saved, we have to unescape
them to get the original string

This shall be used only in tests

We shall use this API in tests where we won't have
MatrixEnc available.

Loading full state requires a lot of bandwidth.  Since
we now load chats from database, we no longer require
loading the complete state.

This shall help speed up loading chats on startup