add contributors

...copied from bitcore. Should also add bitcoinjs-lib contributors.

package.json

@@ -6,6 +6,36 @@
   "scripts": {
     "test": "mocha"
   },
+  "contributors": [
+    {
+      "name": "Gordon Hall",
+      "email": "gordon@bitpay.com"
+    },
+    {
+      "name": "Jeff Garzik",
+      "email": "jgarzik@bitpay.com"
+    },
+    {
+      "name": "Manuel Araoz",
+      "email": "manuelaraoz@gmail.com"
+    },
+    {
+      "name": "Matias Alejo Garcia",
+      "email": "ematiu@gmail.com"
+    },
+    {
+      "name": "Ryan X. Charles",
+      "email": "ryanxcharles@gmail.com"
+    },
+    {
+      "name": "Stefan Thomas",
+      "email": "moon@justmoon.net"
+    },
+    {
+      "name": "Stephen Pair",
+      "email": "stephen@bitpay.com"
+    }
+  ],
   "keywords": [
     "bitcoin",
     "bip32",