Updated MainWindow.java and DetectionTask.java; added option index
recursively, added option index inclusively, implemented filter rule
classes (inclusive and exclusive). Updated FileIndex.java; added .copy()
method which builds and returns a duplicate FileIndex of the calling
FileIndex. Updated and renamed OptionsContainer.java to
OptionContainer.java; added indexRecursively and indexInclusively
options. Removed SettingsContainer.java.
Updated ResultsWindow.java; added a UI component to report the number of
duplicate file groups.
Updated MainWindow.java, FilterContainer.java, DetectionTask.java;
filters will be applied according to whether or not the
inclusive/exclusive filter enable checkboxes are selected.
MainWindow.java: removed unused imports.