Request secure cookie transmission for HTTPS

If cookies are not marked as secure, they can be sent
back by the client on unencrypted channels, disclosing
information. With this fix, clients are requested to
send cookies back on a secure channel in case HTTPS is
used.
Merge pull request #391 from MartinNowack/master

Request secure cookie transmission for HTTPS
Remove unneeded SetSkinName() from webadmin

SetSkinName() was called two times in GetNewUser interface.
Removed the first call because "skin" is a combo box and can't be empty.
route_replies: Add /HELP for some servers
WIP: buffer raw joins/parts/quits/modes