PoC code for pesh, which depends on libreadline.
I opted for using readline because it's widely available.
I still need to find a way to autocomplete sub-commands so the
user can run them directly, and autocompletion should also work.
For example:

	pesh> dos print

Should be equivalent to:

	pesh> dos
	pesh> print

More levels of indirection should be supported as well, for example:

	pesh> imports print characteristics
	pesh> security print certificate

These could be bad examples, but hopefully you get the idea.