Image.getType returns enum, Image enum has names now, fixed Meta ENUM, updated Javadoc

bindings/java/src/org/sleuthkit/datamodel/AbstractFile.java

bindings/java/src/org/sleuthkit/datamodel/Content.java

bindings/java/src/org/sleuthkit/datamodel/Image.java

...ngs/java/src/org/sleuthkit/datamodel/ResultSetHelper.java

bindings/java/src/org/sleuthkit/datamodel/SleuthkitCase.java

bindings/java/src/org/sleuthkit/datamodel/TskData.java

bindings/java/src/org/sleuthkit/datamodel/Volume.java