Suggest a fix if an object fails the be_instance_of matcher but its class has the same name as the expected class

People commonly make the mistake of adding production classes to the spec target as well as the app target, which leads to confusing failures of this sort.
Merge pull request #293 from pivotal-brian-croom/suggest-fix-if-classes-have-same-name-but-different-class

Suggest a fix if an object fails the be_instance_of matcher but its class...