Revert "HCY: add build bits neccesary for compilation"

Revert "HCY: add build bits neccesary for compilation"

This reverts commit 82195e28e3d9f733216f364d20719b213367515f.

The HCY extensions is not ready for use, since the model does not provide
symmmetric conversions. Disabling build and install of it.

pippin@yogi:~/src/babl/tests$ BABL_PATH=../extensions/.libs ./models
HCYA
    test:     0.713 -0.170 -0.020 0.033
    clipped:  -0.505 6.011 -0.259 0.033
    trnsfrmd: 137.334 -0.503 10.838 0.033
HCYA
    test:     0.335 0.130 -0.029 -0.066
    clipped:  0.335 0.130 -0.029 -0.066
    trnsfrmd: 0.335 0.130 -0.029 -0.066
HCYA
    test:     0.455 0.145 0.287 0.409
    clipped:  0.455 0.145 0.287 0.409
    trnsfrmd: 0.455 0.145 0.287 0.409
HCYA
    test:     0.689 -0.154 -0.011 0.077
    clipped:  -0.413 3.381 -0.223 0.077
    trnsfrmd: 55.965 -0.372 4.757 0.077
HCYA is not symmetric
HCY
    test:     0.713 -0.170 -0.020 0.033
    clipped:  -0.505 6.011 -0.259 1.000
    trnsfrmd: 137.334 -0.503 10.838 1.000
HCY
    test:     0.335 0.130 -0.029 -0.066
    clipped:  0.335 0.130 -0.029 1.000
    trnsfrmd: 0.335 0.130 -0.029 1.000
HCY
    test:     0.455 0.145 0.287 0.409
    clipped:  0.455 0.145 0.287 1.000
    trnsfrmd: 0.455 0.145 0.287 1.000
HCY
    test:     0.689 -0.154 -0.011 0.077
    clipped:  -0.413 3.381 -0.223 1.000
    trnsfrmd: 55.965 -0.372 4.757 1.000
HCY is not symmetric