#1 Minor Cleanup of intelhex_readline()

[Robert James Kaes]

Added the <string.h> header to obtain the definition
for strlen().

Removed magic numbers for the carriage return, line
feed, and colon.

Change the fgets() call to use the size of the "line"
buffer, rather
than hard coding the size. Also, the hard-coded size
was one less than
could be used since fgets() already reads in one less
character than the
size provided in order to have room for the NUL.

Removed a second call the strlen() in the CR+LF test.
If the CR was
removed, the length is obviously one less.

[Robert James Kaes]