Version print multibigwigsummary / plotcoverage

[zimoun]

Welcome to deepTools GitHub repository! Please check the following regarding your pull request :

• [ ] Does the PR contain new feature?
• [ ] Does the PR contain bugfix?
• [x] Does the PR contain documentation changes?
• [ ] Does the PR contain changes to the galaxy wrapper?

Since this version is then used by test/test_tools.py, the inconsistency leads to annoyance when packaging downstream