Make sure the client properly reconnects to both Telegram and XMPP after network outage

[ForNeVeR]

Perform the following manual test:

1. Start Emulsion
2. Make sure it connected to both Telegram and XMPP
3. Disable the network connection
4. Enable the network connection
5. Make sure Emulsion works after reconnection

Probably write some unit tests to check that (possibly weak places will be discovered in the process of manual testing).

[ForNeVeR]

Alright it somewhat works, but at the same time it doesn't.

1. When the bot is disconnected, it consumes too much CPU (and it indefinitely spams messages about "Error: One or more errors occurred. (No such host is known)"
2. It looks like everything is pretty much fucked if the network connection isn't available when the bot is started

[ForNeVeR]

2. It looks like everything is pretty much fucked if the network connection isn't available when the bot is started

Interestingly enough, the Telegram side of the bot connects properly then. It looks like the XMPP one is just sending the messages to the wrong actor?

[ForNeVeR]

The issue was that the Telegram actor tried to kill itself via PoisonPill, but it wasn't effective: now-"dead" actor was still receiving the messages again and again. We need to seriously revisit the thread management schema.

[ForNeVeR]

Blocked on: #29, #41, #42.

[ForNeVeR]

Verified, works on current master.