Remove "Error:" prefix from error message

We had already fixed the others, but this one was overlooked.
Update translation template file
Assume inet_pton() is missing on Windows

It's much more difficult to test for this on Windows since the
headers have version guards. Just play it safe and assume it is
missing. We can remove this check when we raise the base requirements
to Vista (or newer).
Fix setsockopt() call on Windows

They use char* rather than void*, requiring a cast here.
Change development version to 1.4.80

The 1.4 branch is now live, so change the version number of the
development builds.