Start an othersites page

This patch:

* Moves the twitter embed to an embeds directory in templates
* Adds a LibraryThing template in the embeds directory in templates
* Starts an othersites page that has sections for our other sites

Todo still:

* Abstract out into a model, so people can easily change/modify which sites
* Make it so that OtherSite objects can also have their own individual pages

Conflicts:

	HedyNet/HedyNet/urls.py
Add ravelry to other sites
Upgrade foundation; use this instead of Ruby gem

This upgrades to the current master branch of foundation,
because the latest release still has the top nav hover
color broken!  This also starts enabling the
foundation 5 grid so we can used medium- classes.
New payments module for managing subscriptions and donations
Remove old donation template
Don't give the impression an actual secret key is in the example.conf
Add othersites app

* Othersites now has a model and admin
* Descriptions display using markdown; site is now configured to use it
* Markdown settings added in to base settings
* Embed templates removed; these are now in the othersite directory
* Added othersites list to site map
* Started using Foundation overrides, to fix previous wipe of
  foundation settings
Add in Google Calendar as an embed
Adjust the top navigation for the new pages
Use twitter embed code from othersites
Add other sites and friends to sitemap and menu
Add markdown requirement for site