Allow zoom below 1.0

[hurzl]

or even to make epub columns smaller than the screen. That would make some texts better readable on big screens (tablets)

[hurzl]

If you don't insist on centering the view, it is enough to change MIN_ZOOM:

-- document-viewer/src/main/java/org/ebookdroid/core/models/ZoomModel.java ---
index 8c549bf4..e9ec981b 100644
@@ -10,7 +10,7 @@
 
 public class ZoomModel extends ListenerProxy {
 
-    public static final float MIN_ZOOM = 1.0f;
+    public static final float MIN_ZOOM = 0.5f;
     public static final float MAX_ZOOM = 32.0f;
 
     private static int ZOOM_ROUND_FACTOR = 0;