S.ex. models: implement support for sample-exact controls in fx-mixer
Works for all faders and send knobs
FxMixer, ValueBuffer, etc. fixes
Merge pull request #799 from diizy/models3

S.ex. models: implement support for sample-exact controls in fx-mixer
when using gcc-4.8.2, desactivate -Werror due to a regression
Merge pull request #805 from ycollet/cmake_gcc_482

Fix a regression with gcc-4.8.2