Improve testing

Summary:
Move dom creation into katex.js so our tests can test non-dom things, and add
some buildTree tests. Add some checks make utils.js work in node. Add support
for jasmine-node, to allow for command line unit testing.

Test Plan:
- Make sure tests work, in both the browser and with `make test`
- Make sure huxley screenshots didn't change

Reviewers: alpert

Reviewed By: alpert

Differential Revision: http://phabricator.khanacademy.org/D13125

package.json

@@ -14,6 +14,10 @@
         "less": "~1.4.2",
         "uglify-js": "~2.4.15",
         "clean-css": "~2.2.15",
-        "huxley": "~0.7.4"
+        "huxley": "~0.7.4",
+        "jasmine-node": "git://github.com/mhevery/jasmine-node.git#Jasmine2.0"
+    },
+    "scripts": {
+        "test": "make test"
     }
 }