dependencies: Set aws-sign as optional dependency

package.json

@@ -27,13 +27,15 @@
     "tunnel-agent": "~0.3.0",
     "http-signature": "~0.10.0",
     "hawk": "~1.0.0",
-    "aws-sign": "~0.3.0",
     "oauth-sign": "~0.3.0",
     "tough-cookie": "~0.9.15",
     "node-uuid": "~1.4.0",
     "mime": "~1.2.9",
     "form-data": "~0.1.0"
   },
+  "optionalDependencies": {
+    "aws-sign": "~0.3.0"
+  },
   "scripts": {
     "test": "node tests/run.js"
   }

request.js

@@ -11,7 +11,7 @@ var optional = require('./lib/optional')
 
   , oauth = require('oauth-sign')
   , hawk = require('hawk')
-  , aws = require('aws-sign')
+  , aws = optional('aws-sign')
   , httpSignature = require('http-signature')
   , uuid = require('node-uuid')
   , mime = require('mime')

tests/test-s3.js

@@ -1,7 +1,15 @@
+try {
+  require('aws-sign')
+} catch (e) {
+  console.error('aws-sign must be installed to run this test.')
+  console.error('skipping this test. please install aws-sign and run again if you need to test this feature.')
+  process.exit(0)
+}
+
 var request = require('../index')
 
-var r = request.get('https://log.curlybracecast.com.s3.amazonaws.com/', 
-  { aws: 
+var r = request.get('https://log.curlybracecast.com.s3.amazonaws.com/',
+  { aws:
     { key: 'AKIAI6KIQRRVMGK3WK5Q'
     , secret: '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'
     , bucket: 'log.curlybracecast.com'
@@ -10,4 +18,4 @@ var r = request.get('https://log.curlybracecast.com.s3.amazonaws.com/',
     console.log(r.headers)
     console.log(body)
   }
-)
+)