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.
I was reporting on **Foo** instead of **class Foo**. This is the VS conversion to set the warning/action/info on a type. 

![image](https://cloud.githubusercontent.com/assets/1558072/5557770/5600e6b6-8cf3-11e4-981f-2d63cbb03b01.png)