Added tracekit as a dependency in component.json to bower to understand

As a workaround to getsentry/raven-js#61 

As side note yesterday I was hitting hard this wall twitter/bower#105 so no matter how, not even with `bower cache-clean && bower install iknite/raven-js --force` bower keep reading offical raven-js files.

I've had to make a clean repo to check things up.