Updated main ReadMe sales pitch.
CacheData added. Closes #154.
Merge branch '2.0-.net4.5' of https://github.com/PureKrome/SimpleAuthentication into 2.0-.net4.5

Conflicts:
	Code/Nancy.SimpleAuthentication/SimpleAuthenticationModule.cs
	Code/SimpleAuthentication.Tests/WebSites/Nancy/SimpleAuthenticationModuleFacts.cs
The IAuthenticationProviderCallback is working!
- Referencing the NancyFX MyGet library for the latest -pre which includes updates to the INancyModule interface.
- Added a NuGet.config file to reference the MyGet api.
- Removed the ICache (fixes #145).
- Removed the HttpClient code. Now uses the WorldDomination.HttpClient.Helpers package instead.
- Provider key is not required to be sent to the Provider. The session now stores this.
- IAuthenticationProviderCallback returns dynamic (closes #155).
- IAuthenticationProviderCallback methods are not async (closes #151).