Ledger integration (#931)

Merges the keybase and Ledger code from go-crypto (which is no more) into the SDK
Adds support for Ledger into gaiacli
Cherry-picks updated error handling from #1158

client/tx/query.go

@@ -2,7 +2,6 @@ package tx
 
 import (
 	"encoding/hex"
-	"encoding/json"
 	"fmt"
 	"net/http"
 	"strconv"
@@ -12,7 +11,7 @@ import (
 	"github.com/gorilla/mux"
 	"github.com/spf13/cobra"
 	"github.com/spf13/viper"
-	abci "github.com/tendermint/abci/types"
+	abci "github.com/tendermint/tendermint/abci/types"
 	ctypes "github.com/tendermint/tendermint/rpc/core/types"
 
 	"github.com/cosmos/cosmos-sdk/client"
@@ -72,7 +71,7 @@ func queryTx(cdc *wire.Codec, ctx context.CoreContext, hashHexStr string, trustN
 		return nil, err
 	}
 
-	return json.MarshalIndent(info, "", "  ")
+	return wire.MarshalJSONIndent(cdc, info)
 }
 
 func formatTxResult(cdc *wire.Codec, res *ctypes.ResultTx) (txInfo, error) {

client/tx/sign.go

@@ -5,7 +5,7 @@ import (
 	"net/http"
 
 	keybase "github.com/cosmos/cosmos-sdk/client/keys"
-	keys "github.com/tendermint/go-crypto/keys"
+	keys "github.com/cosmos/cosmos-sdk/crypto/keys"
 )
 
 // REST request body