Upon login success, the next line was erroneously skipped.

It's still not fully correct, but we don't have existing code that supports
parsing it.

Used the following script:

C_FILES=`git ls-files *.c`
H_FILES=`git ls-files *.h`
for F in "$C_FILES $H_FILES"; do
        echo "$F"
  perl -p -i -e 's/safe_memset\(&\(?([^,]*)\)?,\s*0,\s*sizeof\(\g1\)\)/i_zero_safe(&$1)/g' $F
  perl -p -i -e 's/safe_memset\(([^,]*),\s*0,\s*sizeof\(\*\g1\)\)/i_zero_safe($1)/g' $F
  perl -p -i -e 's/memset\(&\(?([^,]*)\)?,\s*0,\s*sizeof\(\g1\)\)/i_zero(&$1)/g' $F
  perl -p -i -e 's/memset\(([^,]*),\s*0,\s*sizeof\(\*\g1\)\)/i_zero($1)/g' $F
done

managesieve-login: proxy: Did not handle zero return value from managesieve_parser_read_args() correctly.

Also made sure that any capability-derived state information is reset properly before a new capability reply is to be parsed.

Previous change had several problems.

It now uses dsasl-client, so it should now be possible to use SASL mechanisms other than PLAIN.
Cleaned up the code a bit.

Updated version number to v0.4.0 and added a warning to configure.
Applied generic-login.patch.

ManageSieve: added support for reading quoted and literal strings as a stream. Fixes support for handing large SASL responses.
Also resolves long-standing FIXME regarding the second parameter of PUTSCRIPT: it can now be a quoted string.
Includes a few small changes in the login daemon that were done in the dovecot equivalents before.