Fix and update build scripts

[aveXcaesar]

Please check if the PR fulfills these requirements

• I made sure that my code builds
• I merged the master into this branch before pushing
• The commit message follows our guidelines
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

What kind of change does this PR introduce?** (check one with "x")

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Other... Please describe:

What is the current behavior? (You can also link to an open issue here)

closes #161
closes #102

What is the new behavior?

• build.cake completely revised
• Coverage report will be generated on the build script
• Rename test project regarding to naming rules
• Add codecov badget to the readme

Does this PR introduce a breaking change? (check one with "x")

• Yes
• No

If this PR contains a breaking change, please describe the impact and migration path for existing applications

Other information

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (master@2291973). Click here to learn what that means.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             master     #162   +/-   ##
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  Coverage          ?   54.32%           
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  Files             ?       38           
  Lines             ?      959           
  Branches          ?       87           
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  Hits              ?      521           
  Misses            ?      412           
  Partials          ?       26           

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