Crammd5

Rewrite of SendMail function

The SendMail function is rewritten and has the following new functionality:
 - It is optional to skip verification of keys. The config option SKIP_VERIFY is added
 - If the port is 465, or ending on 465, the TLS(/SSL) connection is started first.

- POST /user/repos
- POST /org/:org/repos

increase minimum version for HTTPS to TLS 1.0 (POODLE, fixes #730)

Correction for #723

Correction for #723
Bug was : decode failed if the password contains ```:```

Allow send mail without authentication if SMTP server allow this

Fix spelling errors in comments.

Fix Gravatar images in web view (like commit listing)

Added issue link rendering in commit messages

Related to #700

In the original bug report it was referencing only the sytem avatar images for setup users (like in the header); however the problem also persists with things like commit history.

This commit fixes the `tool.AvatarLink` function so that it also uses the already existing `avatar.HashEmail` function.

I also refactored the `tool.AvatarLink` method some to make the control flow more apparent and adhere better to DRY (there were multiple calls to the `EncodeMd5` function that the `HashEmail` function call replaced, now there is only one.)

According to the [Gravatar API](https://en.gravatar.com/site/implement/hash/) whitespace should also be removed from the email, it was not doing this previously.

Display multi-line commit message on commit diff page.

Use the avatar.HashEmail function instead of hashing email directly.