Machine-readable output

[m-aXimilian]

ToDos

• add schema for xml and json
• add tests (i.e., "basic output works")
• add schema validation tests
• add documentation

Description

This PR introduces a new encoding switch to choose how the CZICheck's result should be emitted to the output.
The switch is exposed as a command line parameter --encoding (-e for short).
One can choose between text (the default and the status quo, i.e., human readable text), json which will emit a json encoded result, and xml which will emit xml-encoded output.
To achieve this, the dependencies rapidjson and pugiXML are introduces to the project.

Note: libxo, as suggested in issue #16 has some shortcomings regarding cross-platform builds (Windows especially). This is why other libraries were used.

Fixes #16 , #23

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Describe the tests that you ran to verify your changes.
Provide instructions to reproduce.

Checklist:

• I followed the Contributing Guidelines.
• I did a self-review.
• I commented my code, particularly in hard-to-understand areas.
• I updated the documentation.
• I have added tests that prove my fix is effective or that my feature works.
• New and existing unit tests pass locally with my changes.

[ptahmose]

version-number and version history need a bump

[ptahmose]

LGTM!
Please consider my remarks and suggestions.

[ptahmose]

LGTM

[m-aXimilian]

I have updated the test script to check (and create) expected results for json and XML output as well in this update
and the respective "good results" in this update
@ptahmose what do you think?