One-off tools

[jcnelson]

Implement one-off command-line tools that are the Syndicate equivalents for:

• ls (DONE)
• cat (DONE)
• mkdir (DONE)
• rmdir (DONE)
• touch (DONE)
• rm (DONE)
• write (DONE)
• trunc (DONE)
• cp
• mv
• attr
• put (DONE)