doc(readme): add license

Add license name and a hint to license file to readme

Closes #13
feat(test): make browser to run tests with configurable

Removes hard coded configuration to use PhantamJS.
Adds ‘browsers’ to spec and e2e config section in system.config.js with ‘PhantomJS’ as default to not change the existing behavior.
Config can be overridden in project.config.js or developer.config.js like every other property from system.config.js

Closes #15