added -v and --version cmd line parameter [skip ci]

this will add a simple command line option (`-v`or `--version`), which will print the current version to stdout and exit if 0. It can be used to determine if something went wrong building a static release (because if this case ther will be an error and an non-zero exit code). I changed the formula, so that travis will only upload the .app if `-v`return a 0 exit code.

Feel free to edit this while merging if you think another versionn number than alpha fits bether ;)