change input interval to tabular

[willemdek11]

FOR CONTRIBUTOR:

• [X] - I have read the CONTRIBUTING.md document and this tool is appropriate for the tools-iuc repo.
• [ ] - License permits unrestricted use (educational + commercial)
• [ ] - This PR adds a new tool or tool collection
• [X] - This PR updates an existing tool or tool collection
• [ ] - This PR does something else (explain below)

FOR REVIEWER:

• [ ] .shed.yml file ok
  • [ ] Toolshed user erasmus-medical-center has access to associated toolshed repo(s)
• [ ] Indentation is correct (4 spaces)
• [ ] Tool version/build ok
• [ ] <command/>
  • [ ] Text parameters, input and output files 'single quoted'
  • [ ] Use of <![CDATA[ ... ]]> tags
  • [ ] Parameters of type text or having optional="true" attribute are checked with if str($param) before being used
• [ ] Data parameters have a format attribute containing datatypes recognised by Galaxy
• [ ] Tests
  • [ ] Parameters are reasonably covered
  • [ ] Test files are appropriate
• [ ] Help
  • [ ] Valid restructuredText and uses <![CDATA[ ... ]]> tags
• [ ] Complies with other best practice in Best Practices Doc

[shiltemann]

thanks @willemdek11