Update to alpine 3.6 and latest dokuwiki

[kalinjul]

trafficstars

Updated to alpine 3.6 (solves PHP bug in alpine 3.5: https://github.com/docker-library/php/issues/376) and dokuwiki 2017-02-19b.

Docker image running these changes is here: https://hub.docker.com/r/julakali/dokuwiki/

Added php7-openssl and php7-zlib for extension downloads and php7-mbstring to support the Dw2Pdf extension.

[cupen]

@julakali sorry this project is no longer maintained, but I fork it and merged your PR here. https://github.com/docker-users/docker-dokuwiki.

[kalinjul]

@cupen: so your fork is the same as mine now: https://github.com/julakali/docker-dokuwiki

There is also a docker image build of this repo: https://hub.docker.com/r/julakali/dokuwiki/