Added class FileSystemUtil
Added class CommandExecutor
Added class LogManager
Global project overhaul
Reviewed exception management in main method.
Grouped binary/repository check inside one method.
Removed useless comments
Added exception management in transfer_backup. Workdir is now cleaned on error.
Added setup_logging method.
commandExecutor transformation from object to module.
fileSystemUtil transformation from object to module.
Updated error message in main method.
PEP-8 compliance.
Merge pull request #6 from deviantony/obj-oriented

Overhaul to use classes & modules. Also PEP-8 compliant.