Add "round ticks" (forwards/backwards) to the same promise chain as Chain.prototype.saveBlock

[karmacoma]

Parent: #302

Continuation of: #1181

Current behavior

BEGIN DB TRANSACTION
  Apply unconfirmed transaction
  Apply confirmed transaction
  Insert block
  Insert transaction
  Insert transaction type
COMMIT

BEGIN DB TRANSACTION
  Round tick
COMMIT

Proposed behavior

BEGIN DB TRANSACTION
  Apply unconfirmed transaction
  Apply confirmed transaction
  Insert block
  Insert transaction
  Insert transaction type
  Round tick
COMMIT

Code Target

https://github.com/LiskHQ/lisk/blob/development/logic/round.js
https://github.com/LiskHQ/lisk/blob/development/modules/rounds.js

[nazarhussain]

@karmacoma After closing #1181 the current behaviour is:

BEGIN DB TRANSACTION
  Apply unconfirmed transaction
  Apply confirmed transaction
  Insert block
  Insert transaction
  Insert transaction type
  BEGIN DB TRANSACTION
      Round tick
  COMMIT
COMMIT

[vitaly-t]

It is currently on hold, as we have absolutely no tests for that functionality, while the change seems trivial.

[4miners]

@vitaly-t I reasigned it, as I need it fixed for #1303

Behavior described in #1297 (comment) is not valid, it still uses different connection handler for tick - so round logic don't see block that is already saved to database (in different SQL transaction).