Modifications proposal

Hi Lars,

Thanks for putting this all together. Great work.

There are some changes I'd like you to take a look at.

- Changed Difficulty value type to Double as the maximum difficulty in BTC can be as big as 2^224
- Changed amounts' value type to Decimal, as Float can only hold 7 decimal places of precision which will cause rounding issues as we need 8 decimal places (BTC network and bitcoin daemon internally represent 1 BTC as 100,000,000 satoshis using 64-bit Int)
- Added some initialization calls to the Console client
- Minor other changes

Please have a look and let me know if you have any thoughts or questions.

G.