mclose - close an opened file
mclose must be used to close a file opened by mopen. If fd is omitted mclose closes the last opend file.
mclose('all') closes all files opened by file('open',..) or mopen
meof, mfprintf, fprintfMat, mfscanf, fscanfMat, mget, mgetstr, mopen, mprintf, mput, mputstr, mscanf, mseek, mtell, file, mdelete,