FileSelector: improved FileSelector to prune branches which do not match the selector "so far". AntPathMatcher is used to determine if a branch should be pruned (traverseDescendants method). Pattern compilation is also cached to improve performance
Added tests in TestFileSelector related to this change.
VFSFactory: use a single FileSystemManager for both ProActive and non-ProActive file systems, the same cache configuration will be used for all file systems.
ProActiveFileObject: override the doListChildrenResolved method to generate an array of FileObjects. This change improves performance drastically in case of a large number of files.
ProActiveFileObject: use the ForkJoin framework to execute in parallel the recursive find algorithm