Fixing some resharper warnings
Refactoring AutoDataTheoryCommand

Extracted the TestMethodNaming class from AutoDataTheoryCommand.
Refactoring the test classes

Used the AutoDataTheory attribute with auto data.
Resharper clean up
Introduced the TypeMembers<T> class

TypeMembers<T> is used to assert invalid arguments with
GuardClauseAssertionon on AutoMoqFixtureTest and
EmptySpecimenCommandTest.
Changed the default post command of AutoMoqFixture

It is appropriate to set SpecimenDefaultValueCommand to the post command
of AutoMoqFixture, because AutoMoqFixture with EmptySpecimenCommand has
same behavior with AutoMoqCustomization.
Added the README file