[Extensions] Module dependencies with an or

[phaidon]

Give the possibility to define module dependencies with or (in Version.php)

e.g. Wikula depends on Wikka or LuMicuLa.

This already exists, e.g. https://github.com/zikula-modules/Clip/blob/master/src/modules/Clip/lib/Clip/Version.php#L67 - or am I missing something?

[Guite]

See http://community.zikula.org/module-Forum-viewtopic-topic-58863-start-0.htm#pid262425

[Guite]

As I understand this case is about having one mandatory dependency, but multiple available options for that.

[phaidon]

It should be like:

At least one of two modules is needed.

@phaidon do you fancy making a PR for this?