feat(tracker): add ecommerce tracking

 - Added support for e-commerce tracking and option to prefix urls for page tracking
 - Added testing for e-commerce tracking
 - Added some documentation
feat(tracker): added setDomainName

add custom domainName support that allow localhost testing
fix #4
Merge remote-tracking branch 'upstream/master'

Conflicts:
	README.md
	src/angular-google-analytics.js
Renamed because component.js is deprecated