Rename `Splitr` -> `Sep`, deprecating old names.  Simplify `initSep` based upon `setDlm.card < seps.len`, also raising exception for bogus `seps`. Update doc comment to be simpler and use separator langauge and work with `nim doc`.
Rename `Splitr` -> `Sep`, deprecating old names.  Simplify `initSep` based
upon `setDlm.card < seps.len`, also raising exception for bogus `seps`.
Update doc comment to be simpler and use separator langauge and work with
`nim doc`.

c-blake/cligen