chore(karma): added test coverage with istanbul
chore(karma): correct the configuration which files should be used for testing
Merge branch develop into feature/code_coverage_client_scripts
chore(karma, grunt): better configuration for codecoverage detection

- grunt converage will execute mocha and karma tests for code coverage
- added an additonal conf for karma codecoverage
Merge branch 'feature/code_coverage_client_scripts' into develop

* feature/code_coverage_client_scripts:
  chore(karma, grunt): better configuration for codecoverage detection
  chore(karma): added test coverage with istanbul