Initial Lightbox UI Creation, Using generic floater reg for now.

indra/newview/app_settings/commands.xml

indra/newview/skins/default/textures/textures.xml

...newview/skins/default/textures/toolbar_icons/lightbox.png

...ewview/skins/default/xui/en/floater_lightbox_settings.xml

indra/newview/skins/default/xui/en/panel_lightbox_dof.xml

indra/newview/skins/default/xui/en/panel_lightbox_image.xml

indra/newview/skins/default/xui/en/panel_lightbox_shadow.xml

indra/newview/skins/default/xui/en/panel_lightbox_ssao.xml

indra/newview/skins/default/xui/en/strings.xml