Add simple rm implementation
Add more '/' checks to rm
Add --verbose support to rm
Implemented sleep, which resolves #38
Implemented --interactive for rm
Documentation changes for rm, resolves #36
Added the aliases -h and -V for --help and --version to sleep
Added the aliases -h and -V for --help and --version to rm
Made sleep suffixes case-insensitive
Implement base64, resolves issue #42
base64: Improve error handling
Use line continuations instead of string addition

I didn't know that line continuations stripped preceding whitespace
Implement tee
link -> crate_id, link is deprecated
link -> crate_id; link is deprecated
Remove Conf struct; put option handling in main

This is more consistent with the other utilities, and probably less
confusing.
Use same crate_id form as other utils
Update crate attributes for tee
Add standard warning function in tee
Rearrange functions in tee