(WEBrick::HTTPServlet::CGIHandler#do_GET): the value of Set-Cookie:
  header field should be splited into each cookie.  [ruby-Bugs:2199]

* lib/webrick/cookie.rb (WEBrick::Cookie.parse_set_cookie): new method
  to parse the value of Set-Cookie: header field.

* test/webrick/test_cookie.rb, test/webrick/test_cgi.rb,
  test/webrick/webrick.cgi: add some test for cookie.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_8@9484 b2dd03c8-39d4-4d8f-98ff-823fe69b080e