A stab at `Create` vs `CreateAnonymous` refactor

This renames all public `CreateAnonymous` to `Create` and adds a "proxy" `[Obsolete]` `CreateAnonymous` to deprecate the existing methods

Based on PR https://github.com/AutoFixture/AutoFixture/pull/89 and could solve Issue https://github.com/AutoFixture/AutoFixture/issues/82