- The default log level in debug builds is now 'info' instead of 'debug'.
- Add option to specify a different log level with the 'GODOT_MONO_LOG_LEVEL' environment variable.
- The name of log files is now a readable date and time.
- Always print the log file path (previously it was printed only it in verbose mode).
This allows more consistency in the manner we include core headers,
where previously there would be a mix of absolute, relative and
include path-dependent includes.
Using `misc/scripts/fix_headers.py` on all Godot files.
Some missing header guards were added, and the header inclusion order
was fixed in the Bullet module.
