Extract logging logic

Previously logging logic was scattered over OS class implementations
with plenty of duplication. Major changes in this commit:

 - Extracted logging logic into a separate Logger hierarchy. It allows
   easy configuration of logging mechanism depending on compile-time or
   run-time configuration.

 - Implemented RotatedFileLogger which is usually used with StdLogger,
   providing persistency of logs. It is often important to be able to
   obtain logs of the game even in production to be able to understand
   what happened prior to some problem. On mobile there previously was
   no way to obtain the logs aside from having the device connected to
   your machine.

 - flush() is not performed in release mode for every logged line. It
   is only performed for errors.

1 files changed, 2 insertions, 1 deletions

diff --git a/main/main.cpp b/main/main.cpp
index 9096b935c2..9ae6d3e92c 100644
--- a/main/main.cpp
+++ b/main/main.cpp
@@ -231,7 +231,6 @@ void Main::print_help(const char *p_binary) {
 }
 
 Error Main::setup(const char *execpath, int argc, char *argv[], bool p_second_phase) {
-
 	RID_OwnerBase::init_rid();
 
 	OS::get_singleton()->initialize_core();
@@ -254,6 +253,8 @@ Error Main::setup(const char *execpath, int argc, char *argv[], bool p_second_ph
 
 	register_core_settings(); //here globals is present
 
+	OS::get_singleton()->initialize_logger();
+
 	translation_server = memnew(TranslationServer);
 	performance = memnew(Performance);
 	globals->add_singleton(ProjectSettings::Singleton("Performance", performance));