dependencies: Set form-data as optional dependency

package.json

@@ -26,10 +26,10 @@
     "forever-agent": "~0.5.0",
     "tough-cookie": "~0.9.15",
     "node-uuid": "~1.4.0",
-    "mime": "~1.2.9",
-    "form-data": "~0.1.0"
+    "mime": "~1.2.9"
   },
   "optionalDependencies": {
+    "form-data": "~0.1.0",
     "tunnel-agent": "~0.3.0",
     "http-signature": "~0.10.0",
     "oauth-sign": "~0.3.0",

request.js

@@ -19,7 +19,7 @@ var optional = require('./lib/optional')
   , _safeStringify = require('json-stringify-safe')
 
   , ForeverAgent = require('forever-agent')
-  , FormData = require('form-data')
+  , FormData = optional('form-data')
 
   , Cookie = require('tough-cookie')
   , CookieJar = Cookie.CookieJar

tests/test-form.js

@@ -1,3 +1,11 @@
+try {
+  require('form-data')
+} catch (e) {
+  console.error('form-data must be installed to run this test.')
+  console.error('skipping this test. please install form-data and run again if you need to test this feature.')
+  process.exit(0)
+}
+
 var assert = require('assert')
 var http = require('http');
 var path = require('path');