Create AllowMembersOrdering Analyser and its tests #76

It is a simple analyser in order to create an entry point for future ordering algorithms.

The analyser creates a hidden diagnostic whereas a type, which can be class or struct, has more than one member. 

I did not include interface on the supported type to be sorted as we agreed on the issue, however I still believe we should.
Why is the diagnostic being reported on column 13? Shouldn't it be reported on the "class Foo" declaration?