core, core/state, trie: EIP158, reprice & skip empty account write

This commit implements EIP158 part 1, 2, 3 & 4

1. If an account is empty it's no longer written to the trie. An empty
  account is defined as (balance=0, nonce=0, storage=0, code=0).
2. Delete an empty account if it's touched
3. An empty account is redefined as either non-existent or empty.
4. Zero value calls and zero value suicides no longer consume the 25k
  reation costs.

params: moved core/config to params

Signed-off-by: Jeffrey Wilcke <jeffrey@ethereum.org>

core/vm/jump_table.go

@@ -16,7 +16,11 @@
 
 package vm
 
-import "math/big"
+import (
+	"math/big"
+
+	"github.com/ethereum/go-ethereum/params"
+)
 
 type jumpPtr struct {
 	fn    instrFn
@@ -25,7 +29,7 @@ type jumpPtr struct {
 
 type vmJumpTable [256]jumpPtr
 
-func newJumpTable(ruleset RuleSet, blockNumber *big.Int) vmJumpTable {
+func newJumpTable(ruleset *params.ChainConfig, blockNumber *big.Int) vmJumpTable {
 	var jumpTable vmJumpTable
 
 	// when initialising a new VM execution we must first check the homestead