Fix WAM Page

https://wikia.fogbugz.com/default.asp?101544
https://wikia.fogbugz.com/default.asp?101530

WamPage extension should not specify exact date that data should come from. We need most recent data and this fix changes it.
Also fixed problem with 2nd january 2012 where we don't have previous data and we are not able to compute wam change (up or down) so with PO we decided to not display data for this date.

@owend @sebastian-wikia @lukaszkonieczny