Disable error tracking on server side
Enable error tracking with a function

	- move ie8/ie9 xdr fix to utils.js
	- wrap error reporter setup into functions
	- enable error tracking only if option is set
Do not disable zones automatically
Add tests

	- Refactor code
	- Make sure error tracking is disabled by default
	- Test enabling error tracking using `enableErrorTracking()`
Fix bug (missing Kadira.models.error)

	- Do not try to track server errors unless error tracking is enabled
Refactor server side error tracking

	- expose Kadira.options
	- en/disable error tracking with Kadira.options.enableErrorTracking
	- fix test
Add methods to enable disable error tracking
Refactor server error tracking

  - always keep an error model
Refactor client side error tracking

	- remove `track...` functions
	- use a flag to check whether to or not to track errors
Merge pull request #65 from mnmtanish/disable-error-tracking

Disable error tracking (by default)