open() returns a tree of data chunks, main() returns 10 results of a command at a time

Signed-off-by: Alexander Ginzburg <alex@eightbits.com>
'base' and 'top' links point to the base and latest hashes of the file data chunks.
open() reads the values of 'base' and 'top' so client can verify who has the latest version

Signed-off-by: Alexander Ginzburg <alex@eightbits.com>