Update msg.json

Fixed few spelling mistakes in Bengali.
Merge pull request #985 from maktrix/patch-1

Update msg.json
1. Using proper polymer events for loading.
2. Fixed proxy control flow to avoid letting 404's through.
3. Removed polymer HTML imports shim.
4. Explicit loading order for ceci components.
5. upgraded polymer to most recent on git for FF compatability (NEEDS ATTENTION)