type cast segments for derived types

[baywet]

fixes #124

Summary

This pull request adds two new settings EnableODataTypeCast (default true) and RequireDerivedTypesConstraintForODataTypeCastSegments (default true) and adds type cast segments for singletons, entity sets, entity set items (keys), navigation properties bound to a single item, navigation properties items (key) of types which have derived types.
It also adds child type operations and child type navigation properties under the singleton, entity set item, single nav prop, and nav prop item cast segments.
It also adds count segments under cast segment that are under collection navigation properties and entity sets.
With examples:

• ~/singleton/ns.typecast + (derived type nav props, derived type operations)
• ~/.../singlenavproperty/ns.type + (derived type nav props, derived type operations)
• ~/.../multiplenavproperty/ns.type + (derived type collection operations, count)
• ~/.../multiplenavproperty/{id}/ns.type + (derived type nav props, derived type operations)
• ~/entityset/ns.type + (derived type collection operations, count)
• ~/entityset/{id}/ns.type + (derived type nav props, derived type operations)

It will read the derived type constraints annotations for example

<Annotation Term="Org.OData.Validation.V1.DerivedTypeConstraint">
          <Collection>
            <String>microsoft.graph.user</String>
            <String>microsoft.graph.group</String>
            <String>microsoft.graph.application</String>
            <String>microsoft.graph.servicePrincipal</String>
            <String>microsoft.graph.device</String>
            <String>microsoft.graph.orgContact</String>
          </Collection>
        </Annotation>

The logic of whether the segments will be added or not can be exhaustively described with

Enable	Require	Annotation	Found in annotation	Result
true	true	true	true	Added
true	true	true	false	Noop
true	true	false	true	Impossible
true	true	false	false	Noop
true	false	true	true	Added
true	false	true	false	Noop
true	false	false	true	Impossible
true	false	false	false	Added
false	true	true	true	Noop
false	true	true	false	Noop
false	true	false	true	Noop
false	true	false	false	Noop
false	false	true	true	Noop
false	false	true	false	Noop
false	false	false	true	Noop
false	false	false	false	Noop

Or segments will only be added when the option is enabled and either:

• annotation is required, present and contains the derived type name
• annotation is not required, and (either annotation is present with the type name or absent)

[xuzhg]

Excuse me. But, Coding style, clean coding, making code readable... are my style. Thanks.

[baywet]

Excuse me. But, Coding style, clean coding, making code readable... are my style. Thanks.

The "Excuse me" part of this passive aggressive comment does not make it more acceptable. IDEs and people are going to have different configurations and preferences. If you care about tab, spaces, curlies and other details like that, please take the time to push a configuration that's enforced through tooling as described in #142 as as we've discussed offline.
Until some systematic linting is in place, arguing about those things and manually fixing those is a waste of time.

Now, can we focus on reviewing the code rather than the whites-pacing around the code please?

[xuzhg]