We now dont get the log files from the text files via chat_log_get_previous() anymore.
We use the sql backend via log_database_get_previous_chat().
So far it just has the same behaviour like chat_log_get_previous(),
except that in _chatwin_history() we don't pass the sender to
win_print_history() which should be fixed in a commit soon.
And log_database_get_previous_chat() can later easily be expanded to fix
https://github.com/profanity-im/profanity/issues/205.
I plan to save all messages in an SQLite db.
For retrieving information it's nicer than having it in a text file.
We will have more info in there and easier to parse it.
This will also be good for later MAM
(https://github.com/profanity-im/profanity/issues/660).
Regular text files will still be an option for users so that they can
easily grep them and do whatever they like.
Internally Profanity will only use the SQLite db.
