Removed ISpecimenBuilderComposer from IFixture,

but add ISpecimenBuilder. This is a good tradeoff, because it makes many
things simpler when ISpecimenBuilderComposer is entirely gone.
Removed ISpecimenBuilderComposer from the DSL

interfaces, but add ISpecimenBuilder as a 'base' interface instead.
Deleted TypedBuilderComposer,

as it was no longer required.
Deleted ISpecimenBuilderComposer.
Deprecated DateTimeGenerator strongly,

so that it's a compiler error to use it. It can be entirely removed in
version 4.0.
Deprecated ConstructorInvoker strongly,

so that it's a compiler error to use it. It can be entirely removed in
version 4.0.
Deprecated CompositeConstructorQuery strongly,

so that it's a compiler error to use it. It can be entirely removed in
version 4.0.
Deprecated IConstructorQuery strongly,

so that it's a compiler error to use it. It can be entirely removed in
version 4.0.
Turned Builders property into a sequence.
Removed some #pragma warning disable statments

that were no longer required.