Ignore properties on array's prototype when iterating.

This fixes a bug where when methods are applied to Array.prototype (e.g. in
Ember.js), analytics would complain about a lot of missing mandatory configs!
added check for hasOwnProprty for remaining `for in` loops
Merge branch 'master' of git://github.com/bskyb-commerce-helpcentre/analytics into bskyb-commerce-helpcentre-master

Conflicts:
	grunt/js/analytics.js
PM|BF: merge in with latest code
PM|BF: protect against array prototype being changed