upgrade requests to 2.5.0
Fix broken caused by Hi-net website update on Dec 1st, 2014

On Dec 1st, 2014, Hi-net website updates using SSL, which makes
authentication complicated. This commit fixes the errors.

1. url change: from www.hinet.bosai.go.jp/REGS
               to hinetwww11.bosai.go.jp/auth
2. from http to https
3. If the user name and password is wrong, the website will redirect
   to the login page, and return a status_code of 302; else return 200.
   The status code is used to check authentication.
4. I don't know why, get method does not work. Just use post method.
5. Username and password are form data, others are query strings.
   So use option `params` and `data` in post.
6. Download using wget failed, just remove it. It's not commonly used.
   Rename cont_download_requests back to cont_download
7. I do NOT understand too much about SSL. It seems the SSL cert of Hi-net
   is not verified. So I just skip SSL verification now. I beleive Hinet.
8. pep8 check