Option "-h" documented, but not functional

[barsnick]

colortail self-documents the -h option, but doesn't implement it correctly:

$ colortail -h
colortail: invalid option -- ?
Try 'colortail --help' for more information.

I'm too lazy to create a PR, since the fix is trivial:

-      c = getopt_long(argc, argv, "qvn:fk:l", long_options, NULL);
+      c = getopt_long(argc, argv, "qvhn:fk:l", long_options, NULL);

Cheers!