code clean;
	add log file path option in setenv.sh, the default value is
		src/lava/magma/runtime/message_infrastructure/log/;

…va-nc/lava into wye_msg_ref_release2_log

	add module: log to file

        add: 2 cmake command line arguments to indicate: which levels log would be recorded, and where printed to.
                - MSG_LOG_LEVEL:
			which levels log would be recorded, valid values:
                          all: all of levels would be recorded;
                          err_warn: both error and warning would be recorded;
                          a number from 0 to 31, consists of followings:
                        	#define LOG_MASK_NULL (0)
                                #define LOG_MASK_INFO (1)
                                #define LOG_MASK_DUMP (1<<1)
                                #define LOG_MASK_DBUG (1<<2)
                                #define LOG_MASK_WARN (1<<3)
                                #define LOG_MASK_ERRO (1<<4)
			DEFAULT VALUE: 16, error log only.
		- MSG_LOG_PRINT_MODE:
			where would log be printed to, valid values:
			  all: both of console and file;
			  file: file only;
			  shell: console only;
			  null: neither
			  a number from 0 to 3, consists of followings:
				#define LOG_PRINT_MASK_NULL (0)
				#define LOG_PRINT_MASK_SHEL (1)
				#define LOG_PRINT_MASK_FILE (2)
			DEFAULT VALUE: 1, console only.

…va-nc/lava into wye_msg_ref_release2_log

	- change: log module indicate if this log need to be printed,
		  except ERR, ERR will be printed whatever the module is.

	- fix: several blank files would be created while log_to_file
is enable but no log message to write.

	- LOG_LEVEL: from bit to number, the lowers will contain the
highers.
	- LOG_PRINT: console always, get FILE setting from compiler
macro.

…va-nc/lava into wye_msg_ref_release2_log