Added osgtexture3D demo, renamed osgtexture demo to osgtexture2D, and have

added osgtexture1D demo which currently is simply copy of osgtexture2D. I
will be modifying it to do 1D texturing next.

Fixed a bug in osg::Texture3D relating to checking of existance of
texturing.

Merged some fixes to the pfb loader from Ulrich Hertlein.

include/osg/Image

@@ -56,9 +56,9 @@ class SG_EXPORT Image : public Object
         
         
         /* allocated a pixel block of specified size and type.*/
-        void createImage(int s,int t,int r,
-                         GLenum format,GLenum type,
-                         int packing=1);
+        void allocateImage(int s,int t,int r,
+                           GLenum format,GLenum type,
+                           int packing=1);
         
         
         /** set the image data and format.
@@ -83,6 +83,13 @@ class SG_EXPORT Image : public Object
         /** Scale image to specified size. */
         void scaleImage(const int s,const int t,const int r);
 
+        /** Copy a source Image into a subpart of this Image at specified position.
+          * Typically used to copy to an already allocated image, such as creating
+          * a 3D image from a stack 2D images.
+          * If the this Image is empty then image data is created to
+          * accomodate the imaging image in its offset position.
+          * If source is NULL then no operation happens, this Image is left unchanged.*/
+        void copySubImage(int s_offset,int t_offset,int r_offset,osg::Image* source);
 
 
         /** Width of image.*/