enable optional scripts option even for release builds

--HG--
branch : scripts-option-rel
extra : amend_source : 52d6c36df5a2db68e44e809e2e264b3318dc1e07
Merged in rglarix/premake-stable-wrk/scripts-option-rel (pull request #46)

reissue #45 - 1 - enable optional scripts option even for release builds