Add initial implementation of block tests

* Add blocktest cmd and support for block tests files in
  tests/BlockTests , the launched node does not connect to
  network, resets state with a genesis block from the test file
  and starts the RPC API

core/chain_manager.go

@@ -231,6 +231,21 @@ func (bc *ChainManager) Reset() {
 	bc.setTotalDifficulty(ethutil.Big("0"))
 }
 
+func (bc *ChainManager) ResetWithGenesisBlock(gb *types.Block) {
+	bc.mu.Lock()
+	defer bc.mu.Unlock()
+
+	for block := bc.currentBlock; block != nil; block = bc.GetBlock(block.Header().ParentHash) {
+		bc.db.Delete(block.Hash())
+	}
+
+	// Prepare the genesis block
+	bc.genesisBlock = gb
+	bc.write(bc.genesisBlock)
+	bc.insert(bc.genesisBlock)
+	bc.currentBlock = bc.genesisBlock
+}
+
 func (self *ChainManager) Export() []byte {
 	self.mu.RLock()
 	defer self.mu.RUnlock()