1.8.0

* New licence: we switched from WTFPL to MIT licence (to prepare wallabag v2)
* Guidelines for contributing to wallabag (PSR-1 and PSR-2)
* Big refactoring in the code (no visible changes for wallabag users)
* rename Home into Unread
* Updated specific configuration for parsing
* Updated polish translation
* Changed default pagination (12 instead of 10)
* Better display when an article contains code (we use highlight.js)
* Added fixtures for MySQL and PostgreSQL installations
* Added email field for user
* Removed availability to download SQLite file (security problem)
* Implemented additional check for using the 'X-Forwarded-Port' header

Fixed bugs:
* Check file permissions at install https://github.com/wallabag/wallabag/issues/584
* Fix to display the login successful message with the translation
* Fix display of 'Done' message when we add a link from 'save a link' item
* Can't import empty file https://github.com/wallabag/wallabag/issues/776
* fix pictures display when DOWNLOAD_PICTURES is enabled