Fixed Sponza loading in EMSCRIPTEN

[maniatic0]

I added a fix to load Sponza in the browser. It embeds the binary into the wasm and loads it in the virtual filesystem. For C++ all of this is invisible..

tiny_bvh version 0.8.3 performance statistics (emcc 3.1 build)
----------------------------------------------------------------
Loading triangle data (262267 tris).
BVH construction speed
warming caches...
- reference builder:  463.07ms for  262267 triangles - 501326 nodes, SAH=214.22
- fast AVX builder:   211.15ms for  262267 triangles - 500482 nodes, SAH=212.78
BVH traversal speed
- CPU, coherent,   basic 2-way layout, ST:   4482.8ms for   7.68M rays =>   1.71MRay/s
- CPU, coherent,   alt 2-way layout,   ST:   4105.7ms for   7.68M rays =>   1.87MRay/s
- CPU, coherent,   soa 2-way layout,   ST:   3937.2ms for   7.68M rays =>   1.95MRay/s
- CPU, coherent,   basic 2-way layout, MT:    837.0ms for   7.68M rays =>   9.18MRay/s
- CPU, coherent,   2-way, packets,     MT:    193.5ms for   7.68M rays =>  39.68MRay/s
- CPU, coherent,   2-way, packets/SSE, MT:    144.8ms for   7.68M rays =>  53.04MRay/s
Optimizing BVH, regular...   done (12.34s). New: 501325 nodes, SAH=181.85
- CPU, coherent,   2-way optimized,    ST:   3047.6ms for   7.68M rays =>   2.52MRay/s
- CPU, incoherent, basic 2-way layout, MT:   1011.5ms for   7.68M rays =>   7.59MRay/s

[jbikker]

Thanks, merged!