Transaction witness support (#2)

* Support encoding/decoding witness and confidential fields

* Add missing fields to Transaction for supporting witness and confidentiality

* Fixes & Refactors hashForWitnessV0

* Fixes due to breaking changes to addInput && fixes copying wtiness from raw && add unit test for hashForWitnessV0

* Add test vectors for hashForWitnessV0

* Lint

* Lint

* Fix due to Transaction.addInut breaking change

src/bufferutils.js

@@ -82,6 +82,18 @@ class BufferWriter {
     this.writeVarInt(vector.length);
     vector.forEach(buf => this.writeVarSlice(buf));
   }
+  writeConfidentialInFields(input) {
+    this.writeVarSlice(input.issuanceRangeProof);
+    this.writeVarSlice(input.inflationRangeProof);
+    this.writeVarInt(input.witness.length);
+    for (const it of input.witness) this.writeVarSlice(it);
+    this.writeVarInt(input.peginWitness.length);
+    for (const it of input.peginWitness) this.writeVarSlice(it);
+  }
+  writeConfidentialOutFields(output) {
+    this.writeVarSlice(output.surjectionProof);
+    this.writeVarSlice(output.rangeProof);
+  }
 }
 exports.BufferWriter = BufferWriter;
 /**
@@ -183,6 +195,23 @@ class BufferReader {
       ]);
     return versionBuffer;
   }
+  readConfidentialInFields() {
+    const issuanceRangeProof = this.readVarSlice();
+    const inflationRangeProof = this.readVarSlice();
+    const witness = this.readVector();
+    const peginWitness = this.readVector();
+    return {
+      issuanceRangeProof,
+      inflationRangeProof,
+      witness,
+      peginWitness,
+    };
+  }
+  readConfidentialOutFields() {
+    const surjectionProof = this.readVarSlice();
+    const rangeProof = this.readVarSlice();
+    return { surjectionProof, rangeProof };
+  }
   readIssuance() {
     const issuanceNonce = this.readSlice(32);
     const issuanceEntropy = this.readSlice(32);

src/psbt.js

@@ -566,7 +566,7 @@ class PsbtTransaction {
         ? bufferutils_1.reverseBuffer(Buffer.from(input.hash, 'hex'))
         : input.hash;
     const script = input.script ? input.script : Buffer.alloc(0);
-    this.tx.addInput(hash, input.index, script, input.sequence, input.issuance);
+    this.tx.addInput(hash, input.index, input.sequence, script, input.issuance);
   }
   addOutput(output) {
     if (