Updated package.json to use new SPDX license exp.

According to the docs on npmjs.com and the warning output when running
`npm install`, the license element in `package.json` was invalid. NPM
has updated their requirements to use the new SPDX license expression
syntax version 2.0, and the license expression that was being used is
now deprecated. I updated the license field to use the new valid
expression. For more information, please see:
https://docs.npmjs.com/files/package.json#license

LICENSE

@@ -0,0 +1 @@
+SEE: http://rem.mit-license.org/

package.json

@@ -11,9 +11,5 @@
     "test": "node test.js"
   },
   "bugs": { "url": "https://github.com/remy/mit-license/issues" },
-  "licenses": [
-    { "type": "MIT",
-      "url": "http://rem.mit-license.org/"
-    }
-  ]
-}
+  "license" : "SEE LICENSE IN LICENSE"
+}