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
And actually it is called in a [block of code](https://github.com/cedricpinson/osg/blame/master/src/osgPlugins/osgjs/GeometryOperation.cpp#L784-820) that is commented and that I was willing to remove but left for now. Wireframe is now handled by [`IndexShape`](https://github.com/cedricpinson/osg/commit/a30bdb1bf4ca33c4e7833fb39fd4f032e4877392) objects .
I'm removing this commented block of code to avoid confusion.