Add "overwrite" and "move contents into" options to place

[OpenBagTwo]

GIVEN Alex has finished setting up her EnderChest and shulker boxes
AND is ready to start placing links
BUT has forgotten to remove a logs folder in one of her instances

WHEN she runs

$ enderchest place

AND she gets the error message:

Error linking shulker box Boxey to instance Instancey:
  instances/Insatancey/.minecraft/logs is a non-empty directory

THEN she should get a prompt that presents her with the following options:

==> How would you like to proceed?
==> [Q]uit, [C]ontinue, [O]verwrite, mo[V]e the contents of this folder into the shulker box?
==> skip the rest of this shulker/instance [M]atch, the rest of this [I]nstance, the rest of this [S]hulker box?
==> or [R]etry?

with V and O options requiring confirmation

SO that she can resolve common place conflicts without having to hop into a file browser

Notes

[OpenBagTwo]

Oh, and for file conflicts (not folder conflicts), obviously "move" isn't an option

[OpenBagTwo]

#94 implemented "retry" so the OP has been rewritten to focus on "overwrite" and "move," which are low priority.