Fix gamma correction on some 3D Tiles.

Author: bagnell

Source/Scene/Cesium3DTileBatchTable.js

@@ -963,7 +963,8 @@ define([
                'void tile_color(vec4 tile_featureColor) \n' +
                '{ \n' +
                '    tile_main(); \n' +
-               '    tile_featureColor = czm_gammaCorrect(tile_featureColor);; \n' +
+               '    tile_featureColor = czm_gammaCorrect(tile_featureColor); \n' +
+               '    gl_FragColor = czm_gammaCorrect(gl_FragColor); \n' +
                '    gl_FragColor.a *= tile_featureColor.a; \n' +
                '    float highlight = ceil(tile_colorBlend); \n' +
                '    gl_FragColor.rgb *= mix(tile_featureColor.rgb, vec3(1.0), highlight); \n' +