Danker

* Added processing timestamps in ISO-8601
* Made computation time compliant to ISO-8601

Adapted scripts to https://phabricator.wikimedia.org/T299947. This is a breaking change and the new code is not compatible to older dumps. Therefore we introduce a new version.

What's Changed
* added environment variable that controls the memory usage and parallelism for all sorts by athalhammer in https://github.com/athalhammer/danker/pull/19


**Full Changelog**: https://github.com/athalhammer/danker/compare/0.7.3...0.7.4

Added repository to Zenodo

Clean-up documentation fixes after 0.7.0 release where the parameters for danker (standalone python library) changed.

Moved from automatic detection and conversion to a flag. Also added a precision parameter for the output scores.