Documentation: Added Connect() Example to README; Updated In-line Documentation

I've added a basic connection example to the README, and have also updated the in-line documentation for Connect() to show the supported arguments more clearly (to avoid having to dig into the source code). Godoc should pick it up and display it beneath the function signature.

I'm also planning to do the same for connection pooling (README example + in-line docs) but I need to figure out a simple example before doing so (tips appreciated!).

Let me know if you want this squashed into a single commit.