direct: remove snake_case alias for CommonFilters.loadShader

See #150 and #147.  Fixes Travis build.

direct/src/filter/CommonFilters.py

@@ -553,7 +553,6 @@ class CommonFilters:
     set_cartoon_ink = setCartoonInk
     del_bloom = delBloom
     del_ambient_occlusion = delAmbientOcclusion
-    load_shader = loadShader
     set_blur_sharpen = setBlurSharpen
     del_blur_sharpen = delBlurSharpen
     del_volumetric_lighting = delVolumetricLighting