[Catalog-sig] Replacement client for pep381client

[Christian Theune]

Hi,

I'm slowly wrapping up my sprint. Here's what happened today:

- fixed some errors reported by users
- allow running a non-deleting mirror (with the hint that official ones 
must not do this)
- add config file handling to avoid complicated command lines including 
some documentation how to handle them
- add test coverage
- add jenkins integration

I got one error regarding filesystem encoding where I noticed that we 
expect that the mirror runs with UTF-8 as the filesystem encoding.
I'm not sure whether just simply encoding the filenames myself is the 
right thing or whether I need to ask operators to tune their 
environment accordingly.

I *guess* that just encoding manually to UTF-8 would be the right thing 
here. Can someone agree or disagree with this?

If you already started using bandersnatch then you need to adapt your 
command line calls once again (the last time) and create a config file.

Christian