Make ref an optional dependency

The ref module adds a compile step even when using the pure-JavaScript client.
This makes the installation optional so if the install fails due to not having
a compiler around you can still use the JavaScript client.

closes #398

lib/types/binaryParsers.js

@@ -1,5 +1,8 @@
+try {
   var ref = require('ref');
   var endian = (ref.endianness === 'LE') ? 'BE' : 'LE';
+} catch(e) {
+}
 
 var parseBits = function(data, bits, offset, invert, callback) {
   offset = offset || 0;
@@ -109,6 +112,9 @@ var parseInt32 = function(value) {
 };
 
 var parseInt64 = function(value) {
+  if(typeof ref == 'undefined') {
+    throw new Error("the ref module is not installed. npm install ref to use the binary parser on bigints");
+  }
   return String(ref['readInt64' + endian](value, 0));
 };
 

package.json

@@ -19,13 +19,15 @@
   "main": "./lib",
   "dependencies": {
     "generic-pool": "2.0.3",
-    "buffer-writer": "1.0.0",
-    "ref": "0.1.3"
+    "buffer-writer": "1.0.0"
   },
   "devDependencies": {
     "jshint": "1.1.0",
     "semver": "~1.1.4"
   },
+  "optionalDependencies": {
+    "ref": "0.1.3"
+  },
   "scripts": {
     "test": "make test-travis connectionString=postgres://postgres@localhost:5432/postgres",
     "install": "node-gyp rebuild || (exit 0)"