Added support for FoundationDB SQL Layer

This pull request adds support for FoundationDB SQL Layer, and reports the results in the README.

Please note there are a few requirements to run the tests in foundationdb.md:

* FoundationDB Key-Value Store (server and client packages)
* FoundationDB SQL Layer
* tmux

Because Key-Value Store enforces a 5 second transaction limit I couldn't run the tests manually. Instead I'm submitting the tests as a batch file while relies on tmux to create the transactions.