Start of idiomatic assertions of basic equality rules

Implements #125
Implemented EqualsNullAssertion

 - Switched all Equals* assertions to override Verify(MethodInfo)
EqualsNullAssertion improvements

 - use ReflectedType
 - test: MethodInfoWithNullDeclaringAndReflectedType
 - Fixed CS0659 compiler warning
 - Improved line widths
Implemented Equals*Assertions

 - Implemented: EqualsNewObjectAssertion, EqualsSelfAssertion, EqualsSuccessiveAssertion
Added CompositeIdiomaticAssertion

Allows composing many idiomatic assertions together. Also, added a scenario that shows it's usage: VerifyCompositeEqualityBehaviourOnManyTypes
Fixes #177 BuildRelease.msbuild AutoFoq
Made CompositeIdiomaticAssertion implement all IIdiomaticAssertion methods
Merge branch '125-idio-equality' of https://github.com/adamchester/AutoFixture into adamchester-125-idio-equality
Incremented minor version,

in order to indicate that the addition of idiomatic assertion of basic
equality rules constitutes a new feature. This resolves #125
(https://github.com/AutoFixture/AutoFixture/issues/125).
Merge branch 'master' into nunit
Incremented version number to 3.8.0