Added starting account nonce feature

Author: vub

ethereum/blocks.py

@@ -852,15 +852,10 @@ def increment_nonce(self, address):
         :param address: the address of the account (binary or hex string)
         :returns: `True` if successful, otherwise `False`
         """
-        return self._delta_item(address, 'nonce', 1)
-
-    def decrement_nonce(self, address):
-        """Decrement the nonce of an account.
-
-        :param address: the address of the account (binary or hex string)
-        :returns: `True` if successful, otherwise `False`
-        """
-        return self._delta_item(address, 'nonce', -1)
+        if self.get_nonce(address) == 0:
+            return self._delta_item(address, 'nonce', self.config['STARTING_ACCT_NONCE'] + 1)
+        else:
+            return self._delta_item(address, 'nonce', 1)
 
     def get_balance(self, address):
         """Get the balance of an account.

ethereum/config.py

@@ -40,7 +40,9 @@
     MAX_EXTRADATA_LENGTH=32,
     # Exponential difficulty timebomb period
     EXPDIFF_PERIOD=100000,
-    EXPDIFF_FREE_PERIODS=2
+    EXPDIFF_FREE_PERIODS=2,
+    # Starting nonce
+    STARTING_ACCT_NONCE=0
 )
 assert default_config['NEPHEW_REWARD'] == \
     default_config['BLOCK_REWARD'] // 32