Break the OS X install specifics to its own file script/setup.osx.
Missed the test from the md5sum hard fail. This fixes the hang on md5 check during setup.
Let the user know we have completed the setup process if we had to run script/setup.
setup.osx file mode a+x.
Add install support for apt (Debian) based systems. This includes Ubuntu.
Actually skip apt packages that are already installed.
Merge pull request #207 from memborsky/modularize-setup

modularize system dependency setup
Correct comment
Fail on non-OS X and Linux platforms
Check apt dependencies in setup.apt itself
Song can work on an absolute path
Song upload endpoint