Provide option for overwriting existing files

[calebtote]

There should exist a procedure which allows for the overwriting of files when attempting to copy files to ZK. Currently, if the file node already exists, an exception is raised, and the execution halted:

Copy failed; it may have partially completed. To return to a stable state, either fix the issue and re-run the command or manually revert.
Failure reason:
znode /path/to/file.yml exists

I can see two possible solutions to this:

1. Rather than raising an exception and exiting, an option for user input could be given:

    znode /path/to/file.yml exists -- overwrite? [Y/n]: 

2. Offering a dedicated command for overwriting existing files, so that you could choose between cp and say, update when sending your file.

[calebtote]

Closed with no comment? :(