Use Henny Penny font for app title

https://www.google.com/fonts#UsePlace:use/Collection:Henny+Penny
Comments in configuration template
Small bugfix for max_delay handling
Fix #29

Configurable antiflood protection for the "Download by URL" feature
Fix bugs

* IO::Socket::SSL dependancy for HTTPS downloads by URL
* error message if the downloaded by URL image is too big
* typo in internationalization call
Improved stats page
Update .gitignore
Remote port detection can now use the X-Remote-Port header if set
Use the X-Forwarded-Proto header to set the scheme to https if needed

The "https" option in configuration file is deprecated and will be removed in 0.4
Update Changelog
Improve default config values

With Mojolicious::Plugin::ConfigHashMerge, it's a lot simplier to have
default config values.

This simplification induces some simplification in other parts of Lutim.
Update README.md for Gitlab's markdown compliance
Fix sentence
Rewrite the shutter plugin from the official documentation
Add the sticker image

Yes, I know, I shouldn't store binary files like this here, but it's the
best place to me : I will not lost them :)