Lut2: fix possibility that the value of lut comes out of the range.
Lut: Implement to take a function and evaluate it to make the lut.
Lut2: Implement to take a function and evaluate it to make the lut.
Hopefully make the pkg-config files behave correctly.
Merge pull request #5 from chikuzen/lut

Add function support to Lut/Lut2