Container lifetimes

Configurable lifetimes for container registrations via the IApplicationRegistrations interface to make it possible to register both singleton and transient dependencies, and request scoped dependencies.

- [x] add lifetime property to the registration types
- [x] create tests for the bootstrapper with request container base class for app and request registrations
- [x] add logic to the bootstrapper with request container base to handle request registrations coming from the IApplicationRegistrations interfaces
- [x] safe rename IApplicationRegistrations to IRegistrations and make sure setting lifetime is possible
- [x] update the registration helpers (the with defaults etc ones) if necessary to accept setting the lifetime
- [x] update DefaultNancyBootstrapper to honour the singleton/transient settings from the registration types
- [ ] update the other request container bootstrappers to honour the singleton/transient settings from the registration types
- [x] update the asp.net bootstrapper (or maybe just delete it? it's not nancy best practice)
- [ ] update the Windsor bootstrapper - it doesn't use a request container, so will need to register with the appropriate per request lifetime