Implemented further analytics by fetching more specific items.

Now fetches:
[x] Pages per visit
[x] Average visit duration
[x] % new visits
[x] Bounce rate
[x] Browser distribution
[x] IE version distribution (can work out from Browser stats)
[x] OS distribution
[x] Language distribution
[x] Location distribution
[x] Mobile device distribution
[x] Top twitter referrals