Gamma correction support for Linux.

We use the code of our fast bilateral filter to implement a tone mapping operator inspired from this SIGGRAPH 02 paper by Frédo Durand and Julie Dorsey. This code is not an exact implementation of this paper. As such, it cannot be used for comparison

C语言查表法实现图像处理算法中伽马校正图像增强-C language look up table method to achieve image processing algorithm gamma correction image enhancement