Support for OpenBSD

OpenBSD grep does not support the \W syntax for matching whitespace. Changed grep (used in the client script) to use [:space:] instead. Fixes OpenBSD syncing and seems well-supported by other platforms.

Amended bash workaround

Alternate approach to fix bash lameness which actually seems to work.

CentOS 7 Compatibility Changes

Added support for base64 formatted file transfers to placate CentOS 7 minimal installs which do not include xxd or bc. Also removed explicit invocation of /bin/sh because that breaks with CentOS's fake sh (symlink to bash). Weirdly, I didn't experience this problem with Debian/Ubuntu's dash symlink. Must be a bash problem.

Version 3 platform release (breaking changes!)

If you're an existing Neskel user please review the README before proceeding. This is a total overhaul which is chock full of breaking changes.

Production release of legacy codebase

It seems silly to tag this as v2.0.0 since the code has been stable and used in production for well over a decade since there's never actually been a formal release even back in the old CVS days. I wanted to set a release/tag for forking development as I dig into a total overhaul.