Added the --date option to the snap subcommand. You can now delete snapshots older than a specific date while creating new snapshots

* Correctly displays help message when no arguments are given

Shortened default help text if nothing is entered on the commandline.

* Added --date option to snap subcommand
Improved commandline help documentation and *list* subcommand output

Changlog update

Updated Readme for version 2

Improved formating of help text

Improved output of *list* subcommand
Improved Sphinx Documentation