Additional properties: created_at, updated_at

* Add MaxDisplayFileSize setting

* Don't show files that are too large

* Localized FileTooLarge

* Change IsFileTooBig => IsFileTooLarge

Adds description, stars_count, forks_count, watchers_count and
open_issues_count.

Executed go fmt

getEngine() not handles DB parameters (#2972) (#2974)

Uses .AllCols() for Update in updateMirror()

Spanish traslation removed

Fixed a wrong way to ommit the --prune option in process.ExecDir() for MirrorUpdate function

Re: issues gogits/gogs#2863 and gogits/gogs#3231

As a result of modifications to the contents of the conf folder, `make bindata`
was run, causing an update to bindata.go.

Meta
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This commit will be rebased onto the 'develop' branch.

This prevents user retrieve arbitrary webhook by changing URL to
access webhook from other unauthorized repositories.

Since . and .. has browser automatical behaviors, we need to disallow those names.

Initially proposed by #2376 and fixes #3068 as well.

- Arbitrary file creation leading to command execution
- .md file creation/deletion

Reported by Gabriel Campana.

QQ STMP host port is 465

host = smtp.qq.com:465

and need the Authorized

"is activate" -> "is activated"

Closes #2764

Also changes the avatar from a jpeg to a png, to allow for
transparent background. The indexed png is also smaller in size.

Note that at the moment the default avatar is only used when
the user requested a custom avatar and the custom avatar file
is not found (should never happen).

In the future the default avatar could be used as a default
return when by-mail avatar lookups fail too (both gravatar
and libravatar support passing a default)

- Update locale bindata

Closes #3192

use 'official' repo.Name instead of incoming repoName; to enforce
correct capitalisation

As you included Czech translation to official distribution, I think I'm missing here.
I know, selfish as hell... ;)

Always send user to settings screen to change avatar.
Drops "change_custom_avatar" localized message, keeps "change_avatar"
for the generic one.

NOTE: only changes the en-US locale, as per
https://github.com/gogits/gogs/wiki/Contributing-Code#those-we-do-not-accept

NOTE: requires rebuild of bindata.go to fully see effects