fixes for ProposerAddress

- state.MakeBlock takes a proposerAddr
- validateBlock only checks that the ProposerAddress is in the validator
  set
- fix raceyness from bad proposer test:
  - use privValidator to get the proposer address (instead of racy
    state)
  - note we had to remove the test that checked the correct proposer was
    included for higher rounds because we don't have a good way to test
    this with multiple consensus states and not using the
    privValidator.Address while calling createProposalBlock was a hack!

blockchain/reactor_test.go

@@ -156,7 +156,7 @@ func makeTxs(height int64) (txs []types.Tx) {
 }
 
 func makeBlock(height int64, state sm.State) *types.Block {
-	block, _ := state.MakeBlock(height, makeTxs(height), new(types.Commit), nil)
+	block, _ := state.MakeBlock(height, makeTxs(height), new(types.Commit), nil, state.Validators.GetProposer().Address)
 	return block
 }