Summary:

- Add "main" field to bower.json to prevent errors during installation.
- Bump version to 0.4.1 in bower.json and package.json

https://github.com/Khan/KaTeX/issues/181

Test plan:
 - Run `bower install katex` from /tmp
 - Verify that there are no errors when running the command
   and that `bower_components/katex/dist/` contains all the build files

Auditors: emily

package.json

@@ -1,6 +1,6 @@
 {
   "name": "katex",
-  "version": "0.3.0",
+  "version": "0.4.1",
   "description": "Fast math typesetting for the web.",
   "main": "katex.js",
   "repository": {