read_file() - read a file into a string
string read_file( string file, int start_line, int number_of_lines );
Read a line of text from a file into a string. The second and third arguments are optional. If only the first argument is specified, the entire file is returned (as a string). The start_line is the line number of the line you wish to read. This routine will return 0 if you try to read past the end of the file, or if you try to read from a nonpositive line.