Rewriting Pidgin code that uses blocking log functions

Pidgin doesn't use threads, so Pidgin's UI maybe frozen by long time operation (like viewing all logs or database operations)

So we definitly need nonblocking log API.

I've just implemented almost all nonblocking log functions, and now I'm rewting Pidgin code that uses old log functions.

It's not simple find and replace, because nonblocking log functions widely use callbacks, so we should change current logic in such way.