Changed target frameworks

- .NET 4 and higher
- Silverlight 4 and higher
- Windows Phone 7.5 and higher
- Windows Store Apps
Changed to readme
Fixed readme formatting
And some more formatting
Item data request and refactoring
Added player image request
Added trade status request
Added some unit tests and removed the IFutRequestFactories interface

The interface is not needed as the func's can return mocks in the tests.
Credits request
Added support for PC accounts
List auction from trade pile request
Removed HTTP method magic strings
Added deserialize method to request base class
AuctionInfo - Changed CurrentPrice to CurrentBid
Tradepile request

Added Tradepile request
Watchlist request

Added Watchlist request
Purchased Items

Added Purchased Items Request
Merge pull request #33 from tringler/master

Watchlist, TradePile and Purchased Items
Updated readme and added the new methods to IFutClient

- Get trade pile
- Watch list
- Purchased items