Failed linting with mytools demo

Dear all,

I tried with planemo (0.62) on Ubuntu 16.04LTS, Python 2.7.12, pip 19.2.3. I followed the quick start instruction by installing planemo, creating a demo directory "mytools", then entered the dir and ran planemo lint and got the following errors.

```
Linting tool /home/jianliang/github/mytools/cat.xml
Applying linter tests... CHECK
.. CHECK: 1 test(s) found.
Applying linter stdio... CHECK
.. INFO: No stdio definition found, tool indicates error conditions with output written to stderr.
Applying linter output... WARNING
.. WARNING: Using format='input' on output data, format_source attribute is less ambiguous and should be used instead.
.. INFO: 1 outputs found.
Applying linter inputs... WARNING
.. WARNING: Param input [input1] with no format specified - 'data' format will be assumed.
.. WARNING: Param input [input2] with no format specified - 'data' format will be assumed.
.. INFO: Found 2 input parameters.
Applying linter help... WARNING
.. WARNING: Help section appears to be empty.
Applying linter general... CHECK
.. CHECK: Tool defines a version [1.0].
.. CHECK: Tool defines a name [Concatenate datasets (for test workflows)].
.. CHECK: Tool defines an id [cat].
.. CHECK: Tool targets 16.01 Galaxy profile.
Applying linter command... CHECK
.. INFO: Tool contains a command.
Applying linter citations... WARNING
.. WARNING: No citations found, consider adding citations to your tool.
Applying linter tool_xsd... CHECK
.. INFO: File validates against XML schema.
Failed linting
Linting tool /home/jianliang/github/mytools/randomlines.xml
Applying linter tests... CHECK
.. CHECK: 2 test(s) found.
Applying linter stdio... CHECK
.. INFO: No stdio definition found, tool indicates error conditions with output written to stderr.
Applying linter output... WARNING
.. WARNING: Using format='input' on output data, format_source attribute is less ambiguous and should be used instead.
.. INFO: 1 outputs found.
Applying linter inputs... CHECK
.. INFO: Found 4 input parameters.
Applying linter help... CHECK
.. CHECK: Tool contains help section.
.. CHECK: Help contains valid reStructuredText.
Applying linter general... CHECK
.. CHECK: Tool defines a version [2.0.2].
.. CHECK: Tool defines a name [Select random lines].
.. CHECK: Tool defines an id [random_lines1].
.. CHECK: Tool targets 16.01 Galaxy profile.
Applying linter command... CHECK
.. INFO: Tool contains a command.
Applying linter citations... WARNING
.. WARNING: No citations found, consider adding citations to your tool.
Applying linter tool_xsd... CHECK
.. INFO: File validates against XML schema.
Failed linting
```
What's wrong? Any suggestions please!! Many thanks.

Cheers,
Jianliang

Reproduce the quick-start setup with planemo 0.62 on the reported Ubuntu and Python versions, then run planemo lint in the mytools directory. Inspect the linting behavior for cat.xml and randomlines.xml, including how the reported warnings affect the final result. Done means the cause of the failed linting is identified and the expected lint outcome is clear.

Written by the indexing model from the issue text.