Update Dockerfile to allow video support

See https://github.com/xbgmsharp/piwigo-videojs/wiki/How-to-add-videos#if-you-are-using-debianubuntu-like-distribution

Update to Piwigo 2.9.3

https://github.com/mathieuruellan/docker-piwigo/issues/11

Method to add/override PHP configuration from files in mounted volume

entrypoint.sh:  For every file in /config/php/apache2.d/, symlink to that file from /etc/php/7.0/apache2/conf.d/

Small README.md fixes

Update Piwigo version to 2.9.2

Update Piwigo version to 2.9.1

- Update Piwigo
- Move from hard coded value to ARG variable

added php5-curl for Social Connect

Update to Piwigo 2.8.2, replace fig with docker-compose