#232 Skip deploys if no changes are generated

Drop support for PHP 5.4 and 5.5 as well as Symfony 2.x (that allows to fix a bug).

#221 & #222 Fix "Symfony ProcessBuilder not found" when running couscous preview

Compatibility with Symfony 4

• #159, #187 Override couscous.yml configuration from command line with the --config key=value option by @cyberbit
• Fix #181 couscous preview : too many arguments by @wysow
• #189 Website update by @wandersonwhcr
• #170 Add new template to the website by @pnowy
• #169 Add documentation for self-update command by @cyberbit

• #165 Automatically exclude directories found in .gitignore (by @jubianchi)
• Bugfix #166 Fix signal handling to avoid unexpected exceptions (by @jubianchi)
• d5548ef Lighter couscous.phar (half the size) by not bundling dev dependencies of Couscous (by @mnapoli) (yes this should have been done sooner :))

• Bugfix #162 Display error output when the preview server goes down (by @jubianchi)
• #158 Add http:// prefix to preview URI in the console (by @Firehed)
• #163 Propagate kill signal to the child server process (by @jubianchi)
• #164 Website design improvement (by @bobmulder)

• #102 #149 New self-update command to update Couscous (by @wysow)
• #142 #147 New include option in configuration, mirroring exclude, to filter directories to process (by @wysow)
• #91 #154 LiveReload for couscous preview (by @wysow)
• #153 Add support for symlinks (by @perchten)
• Documentation updates: #146 by @bobmulder, #148 by @wysow

Nothing has changed except Couscous requires the latest PHP-DI version.