ELB health check interval in line with CF docs

Running a template based on this code produced the following error:
```2014-12-01 13:52:20 UTC  WebsiteElb            CREATE_FAILED         HealthCheck timeout must be less than interval.```

I adjusted the `interval` and `timeout` values to comply with the CF docs.
Update building-blocks.md
Include a real AMI ID so examples can be tested as is.
Include a key_name so resulting instances can be logged into.
Typo
Update README.md
Update website.json
Update README.md with example SF template and number of lines
Merge pull request #16 from ianrossi/master

Some suggested changes to the README.md