Bug 88774 [preferences][content assist] New Jdtcore options to add inside preference page
build I20050322 + Jdtcore head JavaCore#CODEASSIST_FORBIDDEN_REFERENCE_CHECK and JavaCore#CODEASSIST_DISCOURAGED_REFERENCE_CHECK options have been added. If these options are enabled non accessible types will not be proposed by completion. If these options are disabled non accessible types will be proposed but will be less relevant than other completion. JavaCore#CODEASSIST_FORBIDDEN_REFERENCE_CHECK replace the old option JavaCore#CODEASSIST_ACCESS_RESRICTION_CHECK. These new options need to be show inside the code assist preferences.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/preferences/CodeAssistConfigurationBlock.java
public void performDefaults() {
		super.performDefaults();
		initializeFields();
		handleContentAssistColorListSelection();
	}
	
	private void handleContentAssistColorListSelection() {	
		int i= fContentAssistColorList.getSelectionIndex();
		if (i == -1)
			return;
		Key key= (Key) fContentAssistColorListModel[i][1];
		RGB rgb= StringConverter.asRGB(getValue(key));
		fContentAssistColorEditor.setColorValue(rgb);
	}
	protected String[] getFullBuildDialogStrings(boolean workspaceSettings) {
		return null;
	}
	
	/**
	 * Validates that the specified number is positive.
	 * 
	 * @param number
	 *                   The number to validate
	 * @return The status of the validation
	 */
	protected static IStatus validatePositiveNumber(final String number) {
		final StatusInfo status= new StatusInfo();
		if (number.length() == 0) {
			status.setError(PreferencesMessages.SpellingPreferencePage_empty_threshold);