Prototype of workshop homepage validation.

1.  Refactored `tools/check.py` in [workshop-template](https://github.com/swcarpentry/workshop-template) to separate validation checks from command line use.
    *   **To do:** use Python logging instead of global `Error_Messages` variable.
2.  Copied `check.py` into `workshops`.
    *   **To do:** manage this better *without* submodules.
3.  Added view to run validation on a particular event.
4.  Allowed manual override of URL to check via query parameter `?url=https://github.com/something/something`.
5.  Created [https://github.com/swcarpentry/badly-formatted-workshop](https://github.com/swcarpentry/badly-formatted-workshop) for testing.
    *   Run test by going to [http://127.0.0.1:8000/workshops/event/2015-01-14-oxford/validate?url=https://github.com/swcarpentry/badly-formatted-workshop](http://127.0.0.1:8000/workshops/event/2015-01-14-oxford/validate?url=https://github.com/swcarpentry/badly-formatted-workshop).
Finishing first version of workshop website validator.

1.  Synchronizing with recent changes to workshop-template check.py.
2.  Modified view to display message when URL can't be verified.
Merge pull request #111 from gvwilson/checking-workshop-websites

Prototype of workshop homepage validation.