- #2153 remove require for gravatar

We can look at the PushCommits object to see how many commits were
included in a commit, and add some template logic to only show the
comparison link when there are at least 2 commits in a push. We also
correct the link to display the number of commits.

This commit improves templates readability, since all of them use consistent
indent with all template command blocks indented too.

1. Indents both HTML containers such as <div>, <p> and Go HTML template blocks
   such as {{if}} {{with}}

2. Cleans all trailing white-space

3. Adds trailing last line-break to each file

This adds the button to create a new mirror on the dashboard at the same
place where "new repository" and "new organization" already exist.

The hyperlink and the display name of the branch if the branch is in a folder or the branch name has '#'

- #1496: fallback plain text
- #1002: add date header
- #913: fix encoding of header

Signed-off-by: Unknwon <u@gogs.io>