* Check if image value is nil? before creating an image

Check if uploaded images aren't nil before creating SiteUpload models
for them.

* Validate presence of file in SiteUpload

* Fix file presence validation

* Fabricate SiteUpload#file

* Add link to Creative Commons license

* Update annotate to version 2.7.3

* Update aws-sdk-s3 to version 1.9.2

* Update browser to version 2.5.3

* Update capistrano to version 3.10.2

* Update domain_name to version 0.5.20180417

* Update http to version 3.2.0

* Update lograge to version 0.10.0

* Update oj to version 3.5.1

* Update parallel_tests to version 2.21.3

* Update puma to version 3.11.4

* Update rubocop to version 0.55.0

* Update scss_lint to version 0.57.0

* Update simplecov to version 0.16.1

* Update tty-command to version 0.8.0

* Update tty-prompt to version 0.16.0

* Update pkg-config to version 1.3.0

* Update fog-local to version 0.5.0

* Update fog-openstack to version 0.1.25

* Update devise-two-factor to version 3.0.3

* bundle update

* Fix avatar and header issues by using custom geometry detector

Revert a part of #6508. The file passed to dynamic styles method
was not actually a file, but an instance of Paperclip::Attachment,
which broke all styles by always returning {} from the method.

One problem with GIF avatars was that Paperclip::GeometryDetector
reported wrong dimensions for them, e.g. 120x120 GIF avatar would
for some reason be detected as 120x53. By writing our own geometry
parser, we can use FastImage, which also happens to be faster than
ImageMagick, to detect image dimensions, which are also correct.

Unfortunately, this PR does not implement skipping a `convert`
entirely if the dimensions are already correct, as I found no easy
way to write that behaviour into Paperclip without rewriting the
Paperclip::Thumbnail class.

* Only invoke convert if dimension or format needs to be changed

* Add structure for lists

* Add list timeline streaming API

* Add list APIs, bind list-account relation to follow relation

* Add API for adding/removing accounts from lists

* Add pagination to lists API

* Add pagination to list accounts API

* Adjust scopes for new APIs

- Creating and modifying lists merely requires "write" scope
- Fetching information about lists merely requires "read" scope

* Add test for wrong user context on list timeline

* Clean up tests

All the migrations have been updated to use BIGINTs for ID fields in the DB, but ActiveRecord needs to be told to treat those values as BIGINT as well. This PR does that.

* Improve OpenGraph tags for about pages

* Add thumbnail admin setting

* Fix error

* Fix up