Print usage if setup.py is called without arguments.

[Feuermurmel]

This is what distutils does.

[maandree]

I suggest triming the message does to only list the actions such as install and suggest --help for more help.

[JotaRandom]

If the ./setup.py will be tweaked then not forget #176 and #164 maybe something could be done to mitigate the first or implement the latter.

[Feuermurmel]

@jristz I would also go for a rewrite using distutils (or setuptools for that matter). I did not touch any of the code doing the actual install when fixing this issue.

[JotaRandom]

@Feuermurmel Yeah I preffer that, more standard to other python programs and could reduce the source and add the other reature requests, let heard what the others say.

[maandree]

We have a long standing issue about rewritting using distutils.