Shelephant

Bugfix in directory creation. Switching to central function.

* Adding "shelephant_cp" and "shelephant_mv"
* Adding append option to "shelephant_dump"
* Adding squash option to "shelephant_extract"

* Using default sources in `shelephant_send` and `shelephant_rm`.
* Various updates to make the help more readable.
* Adding short options `shelephant_remote`.

* Adding `shelephant_parse`.

* shelephant_get: accepting default source-file

* shelephant_remote: allow update of existing remote file
* shelephant_get: fixing counter
* shelephant_checksum: accepting default source-file
* Checksum: updating chunk size