Merge pull request #595 from wallabag/dev

wallabag 1.6.0
Merge pull request #634 from wallabag/dev

1.6.1
Added PHPePub
Merge pull request #712 from wallabag/dev

1.7, call me "Premium version"
Merge pull request #761 from wallabag/dev

1.7.1
Split up check_setup.php to do a check for the bare essentials (e.g. PHP version) first, then load the config files, etc. and do less important checks which may require access to config variables in the original check_setup.php. Patch fixes #773
Merge branch 'master' into dev