Fix WebGL: INVALID_ENUM: renderbufferStorage: invalid internalformat
Fix WebGL: INVALID_ENUM: renderbufferStorage: invalid internalformat

GL_DEPTH_COMPONENT worked on native but not web, so use
GL_DEPTH_COMPONENT16 which works on both.

satoshinm/NetCraft,satoshinm/NetCraft,satoshinm/NetCraft,satoshinm/NetCraft,satoshinm/NetCraft