Update osgjs skfb

* fixes escaping issue when serializing strings
* fixes compiler warnings
* fixes image path
* adds `resizeTextureUpToPowerOf2` option: **beware** that this changes the default behavior for the pseudo-loader
from our build server: `osg/src/osgPlugins/osgjs/GeometryOperation.cpp:655:23: warning: ‘osg::Geometry* createWireframeGeometry(osg::Geometry&)’ defined but not used [-Wunused-function]`