first implementation for export
refactored and added Tar archive support
added support for Zip files (partial)
reactions to first feedbacks from thaljef
adding a local TODO to track things... to do
Adaptations after feedback from thaljef

Getting rid of multiple-stacks exports
Moving logic for checking inside the Action class
Adapted documentation for single-stack export
Added more to-do's
initial adaptation to single-stack export
Most suggestions from thaljef

* moved to single-stack export
* default filename as STACK-UUIDPREFIX.EXTENSION
* support for tar.gz and tar.bz2
* most validation logic moved in Action class
* hardlinking in directory generation (when possible)
moved TODO in etc/TODO.pod
some tests for Export action
Merge branch 'topic/export' of github.com:polettix/Pinto into polettix-topic/export
Add a copyright declaration to all files in the etc/ directory.

This fixes #104.
Mention copyrights in the change log.
Bump VERSION, regen README.
WIP
automatic support for system and archive tar
merged changes in master
eliminated call to English
first bits for deployable