feat: Adding baseline JavaScript coverage switch

Add the ability to include baseline JavaScript code coverage.

Closes #11
fix improper tabbing
properly declare and export jsInstrumenter variable.

does jsInstrumenter need to be separated out more?
add the correct collector to jsInstrumenter
move getFinalCoverage to the place where collector created
Merge pull request #2 from wubenhe/nchase-feature-karma-coverage-baseline

Nchase feature karma coverage baseline