Add bitcoin-tx tests

Testing: delin, delout, locktime, and basic createrawtransaction-like
functionality.

src/test/data/bitcoin-util-test.json

@@ -5,5 +5,34 @@
   { "exec": ["./bitcoin-tx", "-"],
     "input": "blanktx.hex",
     "output_cmp": "blanktx.hex"
+  },
+  { "exec": ["./bitcoin-tx", "-", "delin=1"],
+    "input": "tx394b54bb.hex",
+    "output_cmp": "tt-delin1-out.hex"
+  },
+  { "exec": ["./bitcoin-tx", "-", "delin=31"],
+    "input": "tx394b54bb.hex",
+    "return_code": 1
+  },
+  { "exec": ["./bitcoin-tx", "-", "delout=1"],
+    "input": "tx394b54bb.hex",
+    "output_cmp": "tt-delout1-out.hex"
+  },
+  { "exec": ["./bitcoin-tx", "-", "delout=2"],
+    "input": "tx394b54bb.hex",
+    "return_code": 1
+  },
+  { "exec": ["./bitcoin-tx", "-", "locktime=317000"],
+    "input": "tx394b54bb.hex",
+    "output_cmp": "tt-locktime317000-out.hex"
+  },
+  { "exec":
+    ["./bitcoin-tx", "-create",
+     "in=5897de6bd6027a475eadd57019d4e6872c396d0716c4875a5f1a6fcfdf385c1f:0",
+     "in=bf829c6bcf84579331337659d31f89dfd138f7f7785802d5501c92333145ca7c:18",
+     "in=22a6f904655d53ae2ff70e701a0bbd90aa3975c0f40bfc6cc996a9049e31cdfc:1",
+     "outaddr=0.18:13tuJJDR2RgArmgfv6JScSdreahzgc4T6o",
+     "outaddr=4:1P8yWvZW8jVihP1bzHeqfE4aoXNX8AVa46"],
+    "output_cmp": "txcreate1.hex"
   }
 ]

src/test/data/txcreate1.hex

@@ -0,0 +1 @@
+01000000031f5c38dfcf6f1a5f5a87c416076d392c87e6d41970d5ad5e477a02d66bde97580000000000ffffffff7cca453133921c50d5025878f7f738d1df891fd359763331935784cf6b9c82bf1200000000fffffffffccd319e04a996c96cfc0bf4c07539aa90bd0b1a700ef72fae535d6504f9a6220100000000ffffffff0280a81201000000001976a9141fc11f39be1729bf973a7ab6a615ca4729d6457488ac0084d717000000001976a914f2d4db28cad6502226ee484ae24505c2885cb12d88ac00000000