Adding a *nix run script for samples.

Adding run.sh to each of the samples.  It mirrors the bat script
already provided for windows.
Updating *nix run scripts according to spacepluk's comments

Quoting the moai bin in the check, changing bash to sh.  Also exiting
on error.
Merge pull request #692 from JandyCo/nix-samples

Adding a *nix run script for samples.