Introduce vpour to CTransaction.

Transactions of version 2 and above contain a `vpour` field which is a vector of `CPourTx`
objects that embody our protocol. We introduce serialization primitives for boost::array
(we intend for changing the amount of inputs and outputs in the circuit to be simple).

SIGHASH_* operations hash this field like any other for now.

src/test/serialize_tests.cpp

@@ -6,6 +6,7 @@
 #include "streams.h"
 #include "hash.h"
 #include "test/test_bitcoin.h"
+#include "utilstrencodings.h"
 
 #include <stdint.h>
 
@@ -15,6 +16,39 @@ using namespace std;
 
 BOOST_FIXTURE_TEST_SUITE(serialize_tests, BasicTestingSetup)
 
+BOOST_AUTO_TEST_CASE(boost_arrays)
+{
+    boost::array<std::string, 2> test_case = {string("zub"), string("baz")};
+    CDataStream ss(SER_DISK, 0);
+    ss << test_case;
+
+    auto hash = Hash(ss.begin(), ss.end());
+
+    BOOST_CHECK_MESSAGE("037a75620362617a" == HexStr(ss.begin(), ss.end()), HexStr(ss.begin(), ss.end()));
+    BOOST_CHECK_MESSAGE(hash == uint256S("13cb12b2dd098dced0064fe4897c97f907ba3ed36ae470c2e7fc2b1111eba35a"), "actually got: " << hash.ToString());
+
+    {
+        // note: boost array of size 2 should serialize to be the same as a tuple
+        std::pair<std::string, std::string> test_case_2 = {string("zub"), string("baz")};
+
+        CDataStream ss2(SER_DISK, 0);
+        ss2 << test_case_2;
+
+        auto hash2 = Hash(ss2.begin(), ss2.end());
+
+        BOOST_CHECK(hash == hash2);
+    }
+
+    boost::array<std::string, 2> decoded_test_case;
+    ss >> decoded_test_case;
+
+    BOOST_CHECK(decoded_test_case == test_case);
+
+    boost::array<int32_t, 2> test = {100, 200};
+
+    BOOST_CHECK_EQUAL(GetSerializeSize(test, 0, 0), 8);
+}
+
 BOOST_AUTO_TEST_CASE(sizes)
 {
     BOOST_CHECK_EQUAL(sizeof(char), GetSerializeSize(char(0), 0));