* Added support for working with BufferHandler
Added `handleBatch` method for TelegramBotHandler and fixed `write` method.
This is necessary to work with BufferHandler, OverflowHandler etc.
Parameters `$level` and `$bubble` are already passed to parent constructor, no need to set them again.
Also setting `$level` without `setLevel()` makes it incomparable as it is not converted to int via `Logger::toMonologLevel()`.
