Several updates to optimize the ServiceStack framework tests.

1. Added SQLite database provider (noted in readme.md but have not hooked to any test scenarios)
2. Fixed an issue with the Update Worlds testing logic to use UpdateAll instead of Update method.
3. Optimized code to use parallelism when determining multiple random numbers - not database calls.
4. Re-factored AppHost code to eliminate duplicate logic between the HTTPListener and Server Hosts.
5. Changed database-specific Route mappings to only map if the database is available & reachable upon start. 
6. Added some preliminary code for the future caching scenarios plus a service request to change the cache provider.