Improve wording for tagged people on tag page

Feature/json exporter

Destroy conversation when all participants leave it

Fix order of poll answers

That causes a cyclic dependency on spring being
loaded otherwise.

BUG: new messages to person that is not sharing

Conversation recipient validated

- Conversation foreign recipient not required to be validated.
- Added 'peter' as spec_helper user.
- New fixture, new statistic values.

- Clearer identifier names

That normalizes any extra / on the base URL.

URI.extract recognized http:// as an URL, causing invalid
associations. #5347 already fixed the parsing, this just
cleans up the caches to get rid of the false associations.

Bye opengraph_parser, hi open_graph_reader

Correctly implement OpenGraph tags

Drop deferred GC and cleanup features/support

Just defining og:site_name indicates that we support the
OpenGraph protocol, but then we didn't set the required
properties.

opengraph_parser is basically unmainted, issues are ignored
or deliberately closed without fixing. It pollutes the global
namespace and has no verification of correctness.

The opengraph gem has basically the same issues, not really maintained,
unreleased patches on master since over a year, not really smart either.

So I created my own version and while at it, why not strive try to be
complete and robust, although it's still a work in progress.

This also improves general URL detection by parsing them
from the message after stripping markdown.

An additional dependency was added to support
fetching sites that require cookies to work at all.
For the same reason Faraday's default redirect limit was
bumped.

Only show aspect chat control if chat is enabled

Stabilize cukes

- Use custom matcher that polls #value of the element
- Wait for the text field to become visible before entering text

on it

Replace spork with spring, update & use binstubs

Fix SlowFinderErrors

move sidekiq configuration from initializer to sidekiq.yml
fixes #5412

Fix delete a photo cuke