Changes

Bug 1241 - Util's Texture.coords (image coordinates) not updated
properly
Adding 'imageTarget', i.e. GL target for this texture or its
sub-components if cubemap The imageTarget preserves the used 2D image
type for the 2D Texture coordinates.
Note: 'Texture.updateImage(final GL gl, final TextureData data, final
int targetOverride)' needs an overhaul targeted for 2.4.0.

Bug 1237: Adopt GlueGen's clarification of IOUtil.getResource(..),
commit d78bb1be0a6290cb94918b21865a023c01825048
- Skip relative lookup for IOUtil.ClassResources using 'asset' only
(from JAR file)
- Tested w/ jar file and build-dir, see scripts/tests.sh 'USE_BUILDDIR'

Bug 1238 - Fix NPE for Window-Icon's PNGPixelRect for unresolved
location; Bug 1199 - Add setting to disable default window icons
Bug 1238 - Fix NPE for Window-Icon's PNGPixelRect for unresolved
location, i.e. null URLConnections
Testing w/ jogl/make/scripts/tests.sh USE_BUILDDIR=1, discloses this
issue - since the icons are available in jar only.
Handling all unresolved resources, i.e. null URLConnection, is required.
Further more, the icon list passed via property 'newt.window.icons' 
shall be separated by comma as well. This allows passing the list via
scripts more conveniently.

-Dnewt.window.icons="newt/data/jogamp-16x16.png,newt/data/jogamp-32x32.png"
+++
Bug 1199 - Add setting to disable default window icons
This patch also allows disabling JogAmp's own window icons by simply
defining a non-existing location, i.e.
 -Dnewt.window.icons="null,null"