Parsing of given file director(s) function.
- give us a better understanding of statics and file descriptors behavior
- have a basic parsing function to use in the next projects
- reads the fd sent in the first parameter
- returns 1 if it finds '\n' in the file with the corresponding line allocated into the second parameter
- returns 0 if EOF
- returns -1 if error
- handles multiple fd simultaneously (thanks to linked lists)
- uses only one static variable