Update session only is value is changed
Code style
Tests for session.HasChanged
update nustache to 1.13.8.22
Added RegisterAll to ApplicationRegistrations
Improved Nancy.Demo.Validation slightly
Improved XML comment of IModelValidator
Massive refactoring of data annotations validation

Removed the old, static, factory that was used to create the adapters
between Nancy.Validation types and the various ValidationAttributes that
are used by Data Annotations

* DataAnnotationAdapters are now registered in the container and later
resolved from there. This means auto-discovery of new adapters + they
can take ctor dependencies just like any other moving part in Nancy

* Added auto-discovery of all the other types that are used by the
Nancy.Validation.DataAnnotations package

* The following types are registered using RegisterWithDefault:
IPropertyValidatorFactory and IValidateableObjectAdapter
Added custom ValidationAttribute to the validation demo project
Cleaned up Data Annotation types
Started fixing test coverage for data annotations
Cleaned up ModelValidationResult
Extracted IPropertyValidator interface
Added tests for DataAnnodationsValidator type
Added tests for DefaultValidatableObjectAdapter type
Fixed test boo-boo
Fixed name of the Nancy.Validation.DataAnnotations.Tests project and namespace
Merge branch 'session-change' of https://github.com/omeaart/Nancy into omeaart-session-change
Styling tweak
Working checking of values changing