Log class name of class if failed to be instantiated

[phillcunnington]

Currently if Cuppa fails to instantiate a test class it does not log the name of that class, only the fact that it failed to instantiate a test class. Logging the name of the test class would add in debugging issues.

[coveralls]

Coverage remained the same at 89.222% when pulling ec3947a on phillcunnington:add_test_class_that_failed_to_be_instantiated into eddd355 on cuppa-framework:master.

[joebandenburg]

Ship it