FIX: Use openpyxl instead of xlrd

Fixes #29 (closed)

Summary

Removes the dependency on the discontinued xlrd<=1.2, uses xlrd>=2.0 for xls files and openpyxl for xlsx files.

Focus

Apparently we waited long enough so that Pandas fixed their engines for reading xls(x) files when both xlrd and openpyxl are installed. So only added a unittest for xls files and removed the version limitation

Test Environment

Simply do the unittests and the integrationtests with the updated xlrd version.

Check List for the Author

Please, prepare your MR for a review. Be sure to write a summary and a focus and create gitlab comments for the reviewer. They should guide the reviewer through the changes, explain your changes and also point out open questions. For further good practices have a look at our review guidelines

• All automated tests pass
• Reference related Issues
• Up-to-date CHANGELOG.md
• Annotations in code (Gitlab comments)
  • Intent of new code
  • Problems with old code
  • Why this implementation?

Check List for the Reviewer

• I understand the intent of this MR
• All automated tests pass
• Up-to-date CHANGELOG.md
• The test environment setup works and the intended behavior is reproducible in the test environment
• In-code documentation and comments are up-to-date.
• Check: Are there spezifications? Are they satisfied?

For further good practices have a look at our review guidelines.

integrationtests/extroot/DataAnalysis/2010_TestProject/2019-02-03/README.md

 ---
 responsible:	
 - Only Responsible
-description: 	A description of another example analysis.
+description: 	A description of this example analysis.
 
 sources:
 - file:	"/ExperimentalData/2010_TestProject/2019-02-03/*.dat"