#182 Massive refactorings to clean up metadata and segment handling

imageio/imageio-metadata/src/main/java/com/twelvemonkeys/imageio/metadata/jpeg/JPEGSegment.java

@@ -53,11 +53,15 @@ public final class JPEGSegment implements Serializable {
         this.length = length;
     }
 
-    int segmentLength() {
+    public int segmentLength() {
         // This is the length field as read from the stream
         return length;
     }
 
+    public InputStream segmentData() {
+        return data != null ? new ByteArrayInputStream(data) : null;
+    }
+
     public int marker() {
         return marker;
     }

imageio/imageio-metadata/src/main/java/com/twelvemonkeys/imageio/metadata/jpeg/JPEGSegmentUtil.java

@@ -106,7 +106,7 @@ public final class JPEGSegmentUtil {
 
                 if (isRequested(segment, segmentIdentifiers)) {
                     if (segments == Collections.EMPTY_LIST) {
-                        segments = new ArrayList<JPEGSegment>();
+                        segments = new ArrayList<>();
                     }
 
                     segments.add(segment);