Edited Task: Add missing configuration convention functionality to lightweight conventions [1044]

There are currently some things that configuration conventions can do that lightweight conventions cannot. We should expose these in lightweight conventions.

Some of examples of this are:

Ignore Type
Associations
IsComplexType
ModelNamespace

Part of this should be to re-visit of whether or not we need an Ignore method on property configuration.

If we are able to include all of the capabilities of configuration conventions in lightweight conventions then we should consider removing configuration conventions.

The design meeting notes for this are here: https://entityframework.codeplex.com/wikipage?title=Design%20Meeting%20Notes%20-%20March%2013%2c%202013