Add file operation logging to the host app

[nextgeniuspro]

This is proposal to add verbose logs from host application so that developer may track in the console all file operations that dreamcast app do. This might be useful for the case when developer want to check, for instance, that when he load a level, all resources of that level were loaded in ram at loading stage and no other file reading operation will occure later, so that he can start music streaming which will not be interruped.

Usage is pretty simple, new command line argument -v after which comma-separated list of needed operation is expected. Example:

dc-tool-ser -t /dev/cu.usbserial-0001 -b 1562500 -v open,stat -x prog.elf

This PR adds logs to all operations that host apps provides, except communication for debugger.

Also, as additional fix was added potential crash of using closed directory, like calling twice closedir for the same directory. While in practice it would be hard to reproduce it still better to have such fix