FIX: XHTML DTD detection

- fixed issue affecting DTD detection for XHTML documents;
  - this needed extra cases adding for each of the XHTML DTD definitions;
- added string constant for XHTML 1.1; and
- added test cases for DTD detection with and without XML declaration.

Closes #904

jhove-bbt/scripts/create-1.31-target.sh

@@ -126,11 +126,21 @@ fi
 
 declare -a tiff_affected=("examples/modules/TIFF-hul/cramps.tif.jhove.xml"
 				"examples/modules/TIFF-hul/text.tif.jhove.xml"
-				"examples/modules/TIFF-hul/testpage-small.tif.jhove.xml"
-				)
+				"examples/modules/TIFF-hul/testpage-small.tif.jhove.xml")
 for filename in "${tiff_affected[@]}"
 do
 	if [[ -f "${candidateRoot}/${filename}" ]]; then
 		cp "${candidateRoot}/${filename}" "${targetRoot}/${filename}"
 	fi
 done
+
+declare -a xhtml_affected=("errors/modules/HTML-hul/xhtml-trans-no-xml-dec.html.jhove.xml"
+				"errors/modules/HTML-hul/xhtml-strict-no-xml-dec.html.jhove.xml"
+				"errors/modules/HTML-hul/xhtml-frames-no-xml-dec.html.jhove.xml"
+				"errors/modules/HTML-hul/xhtml-1-1-no-xml-dec.html.jhove.xml")
+for filename in "${xhtml_affected[@]}"
+do
+	if [[ -f "${candidateRoot}/${filename}" ]]; then
+		cp "${candidateRoot}/${filename}" "${targetRoot}/${filename}"
+	fi
+done

jhove-modules/html-hul/src/main/java/edu/harvard/hul/ois/jhove/module/HtmlModule.java

@@ -102,6 +102,7 @@ public class HtmlModule extends ModuleBase {
 	private static final String HTML_4_0 = "HTML 4.0";
 	private static final String HTML_4_01 = "HTML 4.01";
 	private static final String XHTML_1_0 = "XHTML 1.0";
+	private static final String XHTML_1_1_STR = "XHTML 1.1";
 
 	private static final String NAME = "HTML-hul";
     private static final String RELEASE = "1.4.3";
@@ -162,7 +163,7 @@ public class HtmlModule extends ModuleBase {
 	/* Version names, matching the above indices */
 	private static final String[] VERSIONNAMES = { null, "HTML 3.2", HTML_4_0,
 			HTML_4_0, HTML_4_0, HTML_4_01, HTML_4_01, HTML_4_01, XHTML_1_0,
-			XHTML_1_0, XHTML_1_0, "XHTML 1.1" };
+			XHTML_1_0, XHTML_1_0, XHTML_1_1_STR };
 
 	/* Flag to know if the property TextMDMetadata is to be added */
 	protected boolean _withTextMD = false;
@@ -675,7 +676,15 @@ protected int checkDoctype(List elements) {
 						return HTML_4_01_TRANSITIONAL;
 					case "-//W3C//DTD HTML 4.01 FRAMESET//EN":
 						return HTML_4_01_FRAMESET;
-					default:
+                    case "-//W3C//DTD XHTML 1.0 STRICT//EN":
+                        return XHTML_1_0_STRICT;
+                    case "-//W3C//DTD XHTML 1.0 TRANSITIONAL//EN":
+                        return XHTML_1_0_TRANSITIONAL;
+                    case "-//W3C//DTD XHTML 1.0 FRAMESET//EN":
+                        return XHTML_1_0_FRAMESET;
+                    case "-//W3C//DTD XHTML 1.1//EN":
+                        return XHTML_1_1;
+                    default:
 						break;
 				}
 		} catch (Exception e) {