Simple PoC of site search using swiftype

The integration of [Swiftype](swiftype.com) looked so easy I thought I'd try it out on emberjs.com. It seems to work quite well considering the minimal effort needed to get it going...

Gives full site search including the API docs, guides and blog posts!

If you think this is a good idea I can transfer the account to the relevant people so you can edit results & view analytics.

May satisfy issue #145.

**Note**: swiftype is in free public beta but [will start charging](https://swiftype.com/pricing) for the service in the future for heavy usage. Whether this would apply to emberjs.com is unclear but may be at least a decent interim solution?