First drop of samples from scalable apps tour.

Here are the samples that we ran (for the purpose of illustrating some points, not really to drill into these specific implementations) at the events in the past two weeks. These are not demos that illustrate scalability per-se. We couldn't carry enough laptops with us to illustrate scalability for real. These demos deal with transactions, layers and performance tuning. (Reminder: Performance has little to do with throughput -- think about all the time people spend in traffic jams with their Porsche 911 running in idle).