[CTL-5] (+) Initial commit for Interception Extension.
[CTL-5] Added first version of Interception unit tests.
(+) Added the CreateCallBackHandler method in InterceptorHandler class to make the callback handler instanciation easier.
[CTL-5] Code review.
Merge remote-tracking branch 'origin/Interception' into develop

Conflicts:
	src/Catel.Extensions.Interception/Catel.Extensions.Interception.NET40/Catel.Extensions.Interception.NET40.csproj
	src/Catel.Extensions.Interception/Catel.Extensions.Interception.NET40/ModuleInitializer.cs
	src/Catel.Extensions.Interception/Catel.Extensions.Interception.NET40/packages.config
	src/Catel.Extensions.Interception/Catel.Extensions.Interception.NET45/Catel.Extensions.Interception.NET45.csproj
	src/Catel.Extensions.Interception/Catel.Extensions.Interception.NET45/packages.config