Refactored BTCChina

Changes:

Added *Raw layer for all three polling services
 - @Override, verify() left in generic services, removed from *Raw layer

Reflected changes in examples
 - all examples show generic() and raw() methods of doing the same thing.
 - commented out the withdraw portion of the account example; will throw a error because of lack of rights.

Nonce logic changed slightly:
 - Added lastNonce, will increment by 1 if current nonce is equal to the last nonce sent.

Code audit & comments are much welcomed! :)

BTC Address: 16HQ6vU58THxHvLS7Qx9Es8uvTWAtwHyGr

Cheers!