Ensure all MOF parameters are returned in WSManListener - Fixes #21

[PlagueHO]

Pull Request (PR) description This PR ensures that Get-TargetResource in WSManListener resource returns all the parameters in the MOF file.

It also corrects some style issues.

This Pull Request (PR) fixes the following issues:

• Fixes #21

Task list:

• [x] Change details added to Unreleased section of CHANGELOG.md?
• [ ] Added/updated documentation, comment-based help and descriptions in .schema.mof files where appropriate?
• [ ] Examples appropriately updated?
• [x] New/changed code adheres to Style Guidelines?
• [x] Unit and (optional) Integration tests created/updated where possible?

@Johlju - would you mind reviewing this one for me?

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This change is 

[codecov[bot]]

Codecov Report

Merging #22 into dev will increase coverage by <1%. The diff coverage is 77%.

@@        Coverage Diff         @@
##           dev   #22    +/-   ##
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+ Coverage   88%   89%   +<1%     
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  Files        2     2            
  Lines      239   258    +19     
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+ Hits       212   230    +18     
- Misses      27    28     +1