class GammaCorrectionTest_SomeCorrectedSomeNot_Test

We draw the following scene:

+--------+---------+---------+---------+

| ǁ |

| ǁ |

| ǁ |

+ ǁ |

| ǁ |

| ǁ |

| not ǁ |

+ gamma ǁ gamma |

| corrected ǁ corrected |

| ǁ |

| ǁ |

+ ǁ |

| ǁ |

| ǁ |

| ǁ |

+--------+---------+---------+---------+

A rectangle and a square a drawn, both with the same color texture, with gamma

correction applied only to the rectangle. The rectangle is drawn above the square,

on the right half of the output image.

1/2 of the area should be kColor (1, .8, .4, 1);

1/2 of the area should be gamma-corrected kColor (1, .64, .16, 1);

(i.e. the RGB components are squared)