added TTL index on collection
test takes over 1 minute to run, because of the way TTL collections are cleared!
dropped .net version to 4.0
added nuget pkg
Merge branch 'master' of github.com:alexjamesbrown/AspNetWebApi-OutputCache-MongoDb

Conflicts:
	WebAPI.OutputCache.MongoDb.Tests/MongoDbApiOutputCacheTests.cs
updated to use Strathweb.CacheOutput.WebApi2 -
Only supports WebApi2 for time being
updated Nuget pkg