keep the API complete at all times

An Alexander Krasnostavsky fix.

to/from, based on a suggestion from Alexander Krasnostavsky

doing proxy authentication.

previous difference was not clear nor documented properly). They can now both
be used interchangeably, but we prefer UPLOAD to PUT since it is a more
generic term.

might be done differently in the future.

function fails and it returns NULL

if a connection is tunneled through a proxy. A tunnel is done with CONNECT,
either when using HTTPS or FTPS, or if explicitly enabled by the app.

both with older libidn versions without idn_free() and with libidn versions
that gets installed without idn-free.h

 Gisle's previous mail. We now use this function, and thus we require libidn
 0.4.5 or later. No earler version will do.

not be used both in one request. Fixed it and added test case 172 to verify.

set to the domain .a.b.c (that is with a dot prefix). This is now fixed and
test case 171 verifies it.

once and for all

deleted trailing whitespace

properly
+ delete trailing whitespace

about that passed-in argument not being used.
* killed trailing whitespace