JMS #38: Some major optimizations for the sessions middleware.

Sessions is still in a weird state. I will get it cleaned up and
have more tests. So far it is looking far better than it was
JMS #38: Formatting
JMS #38: Cleaned up benchmarks
JMS #38: Refactored a bit
JMS #38: Error handling for store.Get
JMS #38: Added flashes back. This time with tests
JMS #38: Formatting