Mac OS X fix: no ALUT framework

Currently, when using ALUT in a project on Mac OS X Yosemite (clang), linking fails because no framework is found:
 
    Linking dist/build/music/music ...
    ld: framework not found ALUT
    clang: error: linker command failed with exit code 1 (use -v to see invocation)

This pull request fixes this by not using an alut framework but working with extra-libraries.
Prerequisit to it working is installing freealut (brew install freealut with homebrew), since that's what ultimately used in the linked executable.