Removed caller from tx and added "callership" to account.

Transactions can no longer serve as callers. Accounts are now the
initial callee of closures. Transactions now serve as transport to call
closures.

ethchain/state.go

@@ -86,9 +86,9 @@ func (s *State) UpdateContract(addr []byte, contract *Contract) {
 func (s *State) GetAccount(addr []byte) (account *Account) {
 	data := s.trie.Get(string(addr))
 	if data == "" {
-		account = NewAccount(big.NewInt(0))
+		account = NewAccount(addr, big.NewInt(0))
 	} else {
-		account = NewAccountFromData([]byte(data))
+		account = NewAccountFromData(addr, []byte(data))
 	}
 
 	return