Rename exception classes

[vruusmann]

The following two exceptions are throws to indicate a structural problem with a PMML document:

• org.jpmml.evaluator.InvalidFeatureException
• org.jpmml.evaluator.UnsupportedFeatureException

Unfortunately, the use of a substring "feature" is confusing, because it might lead end users to believe that there is something wrong with input data (as "feature" is commonly used to refer to input fields).

Therefore, the substring "feature" could be replaced with a substring "markup":

• org.jpmml.evaluator.InvalidMarkupException
• org.jpmml.evaluator.UnsupportedMarkupException

[vruusmann]

This rename should be implemented in the 1.4.X development branch.