JarAccess should ignore .class entries in jar files

Memory problem were reported https://community.jboss.org/message/804026#804026

JarAccess is used by internal model to optimize requests to jar files. It builds a map that binds parent folder path to its content. At present, maps include paths for all entries so that in a large workspace with 500-1000 jars memory consumed by these maps may add up to 70Mb. However, for a long time .class entries from JarAccess are not used directly for presentation in ui. Class selector based on it had been replaced by Eclipse's Class selector years ago. Builders in CDI and Seam get classes from JDT model. Open-ons work with JDT elements as well. Hence, if internal model has no more data on .class entries, it should not affect anything, while the profit is significant - memory consumed by maps in JarAccess may drop 5 to 10 times.