Simplify logging

[zilder]

This is just a proof of concept, actual macro name may be changed in final version. But the general idea is to simplify the way logging is implemented. Namely it requires developer to specify __FILE__ and __LINE__ macros manually. In this PR i introduce logger_log_fileinfo function similar to logger_log with the only difference that it accepts extra file and line number arguments. Also log macro was introduced which automatically puts file and line number in the function call. This design particularly allows to use log without any format arguments like this:

log("some error message");

I left the original logger_log func calls in the places where __FILE__ and __LINE__ hadn't been used. Probably it makes sense to make them uniform and use the new log macro instead.