Update index.md

- Updated VVV repo URL to the new organization-based one.
- Added new trunk SVN repo that contains source, tools, tests, and build tools for Grunt.
Removed Bitbucket core repo link.

The core repo on Bitbucket has been removed. It's replacement is now on Kiln, which forces you to sign in to view the code.

```
Our apologies, but the repository "WordPress" has been deleted.
It now lives at https://mirrors.kilnhg.com/Code/Mirrors/PHP/WordPress.
```
Merge pull request #58 from morganestes/patch-1

Sure thanks - Updating VVV link