[#1002]  Remove chevah.utils dependency

Problem description
===================

reviewers @alibotean 

chevah.compat should be an independent package dealing only with low-lever OS compatibility tasks.

We don't it to depend on utils, so that it can be used in other projects, without requiring chevah.utils as an extra dependency.

It will still depend on chevah.empirical... but only for running the tests.

Changes description
===================

All chevah.utils code was removed.

I have renamed the 'factory' object used for generating testing object, with "manufacturer".
This should avoid confusion when testing real factory object like FTPFactory 

The problem is that with the previous version chevah.compat was using some code/elements/object specific to SFTPPlus Server.

The interfaces and exceptions are now "standalone" and don't require any other package. Details about how "exceptions" and "errors" are handles are found on the internal wiki page.

Exceptions handling is not 100% fixed and will be fixed in #1050.

The branch is already humongous.


Many of the changes are just renaming to import from chevah.compat instead of chevah.utils.

There is also some code moved from utils.

There will be follow up branches for chevah.server and chevah.utils to use this new package.


How to try and test the changes
===============================

Clean your build system, run paver deps again and run all tests.