Cleanup package.json

Add a license, main file, and add missing huxley dependency

Auditors: alpert

package.json

@@ -2,15 +2,18 @@
     "name": "katex",
     "version": "0.0.1",
     "description": "Fast math!",
+    "main": "katex.js",
     "repository": {
         "type": "git",
         "url": "git://github.com/Khan/KaTeX.git"
     },
+    "license": "MIT",
     "devDependencies": {
         "browserify": "~2.29.1",
         "express": "~3.3.3",
         "less": "~1.4.2",
         "uglify-js": "~2.4.15",
-        "clean-css": "~2.2.15"
+        "clean-css": "~2.2.15",
+        "huxley": "~0.7.4"
     }
 }