gendocs years and urls

[Karl Berry]

Ludo (and all),

0) Since you wanted to take over gendocs, and since (I guess) you wanted
to maintain it in gnulib, do you follow bug-gnulib?  I don't see your
address(es), but maybe you read it through gmane or whatever.

1) regarding gendocs_template{,_min}, they were munged by the global
gnulib copyright update to say "2014-2015", but it's conventional for
such template files to just have the current year ("2015"), like version
strings.

2) regarding gendocs.sh,
2a) the copyright year list is wrongly missing 2014,
2b) the version string still says 2013 instead of 2015,
2c) the help message still refers to (stale) texinfo urls and bug-texinfo.

Karl