Specify Model Attributes at runtime when creating tables

This feature furthers ServiceStack.OrmLite's goal of supporting true
POCO and not requiring attributes in the Business layer.

Sometimes you are dealing with a Model library which cannot or should
not have dependencies on ServiceStack.Net, and/or you cannot or do not
want to decorate the Classes and Properties with data annotation
attributes. In the data access layer you may still want to make use of
the features the attributes provide in the Dal, such as the
AutoIncrementAttribute, ForeignKeyAttribute, etc.

This commit adds support for this functionality via the new
DataAnnotationsCollection class, optionally accepted by CreateTable and
its overloads.

If this sounds confusing, view the [examples in the Readme.md](https://github.com/eggnog/ServiceStack.OrmLite/blob/20960e94fc36321ca2eda457570c4e1cf56624cc/README.md#applying-attributes-to-classes-at-runtime) and you 
will see how simple it is.