Return the next line of the file as a string.
FGETS(FID) returns the next line of a file associated with file
identifier fid as a MATLAB string. The newline IS included.
Use FGETL () to get the next line WITHOUT the newline included.
If just an end-of-file is encountered then -1 is returned.
IMPORTANT: Please note that this is intended to be used ONLY with
text files. If by mistake you read a "binary" file
without newline characters this routine may take a
long time for large files.